Showing papers on "Schottky diode published in 2021"
98 citations
TL;DR: By using density functional theory and ab initio quantum-transport simulation, Wang et al. as discussed by the authors studied the Schottky barrier and the rectifying behavior of diodes consisting of the two-dimensional metal phase $1T\text{\ensuremath{-}}{\mathrm{MoS}}_{2}$ and semiconductor phase 2H-${ MoS}}
Abstract: By using density functional theory and ab initio quantum-transport simulation, we study the Schottky barrier and the rectifying behavior of diodes consisting of the two-dimensional metal phase $1T\text{\ensuremath{-}}{\mathrm{MoS}}_{2}$ and semiconductor phase 2H-${\mathrm{MoS}}_{2}$. The results show that the Schottky barrier of the out-of-plane (OP) contacted ${\mathrm{MoS}}_{2}$ heterostructure diode is a little different from that of the in-plane (IP) contacted ${\mathrm{MoS}}_{2}$ heterostructure diode. The current-voltage characteristics show that the OP diode has the better rectifying behavior compared to the IP diode under the zero gate voltage. The corresponding maximum rectifier ratio of the OP Schottky barrier diode is close to ${10}^{7}$ at 0.9 V bias voltage. More interestingly, we find that the gate voltage can be used to effectively control the rectifying behavior of the two diodes. The positive gate voltages can increase the current value of two Schottky barrier diodes, but weaken their rectification ratios. The negative gate voltages can reverse the rectifying direction of two Schottky barrier diodes. The above results provide good theoretical guidance for the designing of diode devices based on two-dimensional materials in the future.
79 citations
TL;DR: In this article, the authors demonstrate the first vertical β-Ga2O3 junction barrier Schottky (JBS) diode with the implementation of thermally oxidized p-type NiO to compensate for the dilemma of the forfeit of the p-Type β-GAspO3.
Abstract: In this article, we report on demonstrating the first vertical β-Ga2O3 junction barrier Schottky (JBS) diode with the implementation of thermally oxidized p-type NiO to compensate for the dilemma of the forfeit of the p-type β-Ga2O3. With this wide-bandgap p-type NiOx, β-Ga2O3 JBS diodes with an area of 100 × 100 μ m2 achieve a breakdown voltage (BV) and specific on -resistance R on,sp of 1715 V and 3.45 mΩ·cm2, respectively, yielding a Baliga's figure of merit (FOM) of BV2/ R on,sp = 0.85 GW/cm2, which is the highest direct-current FOM value among all β-Ga2O3 diodes. Meanwhile, a large size JBS diode with the area of 1 × 1 mm2 shows a forward current IF and BV of 5 A/700 V, which is also the best IF and BV combinations (FOM = 64 MW/cm2) among all published results about large-area Ga2O3 diodes. Dynamic switching characteristics reveal that the diode suffers from a negligible current collapse phenomenon even at a −600 V and 103 s stress, showing the great promise of implementing p-NiO in the future β-Ga2O3 power electronic devices.
69 citations
TL;DR: In this paper, a Ga2O3 field-plated Schottky barrier diode (SBD) with a novel extreme permittivity dielectric field oxide was used to enable a punch-through (PT) field profile and very low differential specific on-resistance.
Abstract: We report a vertical (001) $\beta $ -Ga2O3 field-plated (FP) Schottky barrier diode (SBD) with a novel extreme permittivity dielectric field oxide. A thin drift layer of $1.7~\mu {m}$ was used to enable a punch-through (PT) field profile and very low differential specific on-resistance ( $\text{R}_{\text {on-sp}}$ ) of 0.32 $\text{m}\Omega $ -cm2. The extreme permittivity field plate oxide facilitated the lateral spread of the electric field profile beyond the field plate edge and enabled a breakdown voltage ( ${V}_{\textit {br}}$ ) of 687 V. The edge termination efficiency increases from 13.2% for non-field plated structure to 61% for high permittivity field plate structure. The surface breakdown electric field was extracted to be 5.45 MV/cm at the center of the anode region using TCAD simulations. The high permittivity field plated SBD demonstrated a record high Baliga’s figure of merit (BFOM) of 1.47 GW/cm2 showing the potential of Ga2O3 power devices for multi-kilovolt class applications.
69 citations
TL;DR: In this paper, a better tradeoff between fast reverse-recovery and rugged surge-current capability has been demonstrated in NiO/Ga2O3 p-n heterojunction diodes (HJDs).
Abstract: Ga2O3 power diodes with high voltage/current ratings, superior dynamic performance, robust reliability, and potentially easy-to-implement are a vital milestone on the Ga2O3 power electronics roadmap. In this letter, a better tradeoff between fast reverse-recovery and rugged surge-current capability has been demonstrated in NiO/Ga2O3 p-n heterojunction diodes (HJDs). With the double-layered p-NiO design, the HJD exhibits superior electrostatic performances, including a high breakdown voltage of 1.37 kV, a forward current of 12.0 A with a low on-state resistance of 0.26 Ω, yielding a static Baliga's figure of merit (FOM) of 0.72 GW/cm2. Meanwhile, the fast switching performance has been observed with a short reverse recovery time in nanosecond timescale (11 ns) under extreme switching conditions of d i /d t up to 500 A/μs. In particular, for a 9-mm2 HJD, a large surge current of 45 A has also been obtained in a 10-ms surge transient, thanks to the conductivity modulation effect. These results are comparable with those of the advanced commercial SiC SBDs and have significantly outperformed the past reported Ga2O3 HJDs, fulfilling the enormous potential of Ga2O3 in power applications.
68 citations
TL;DR: In this article, a defect healing method is used to tune the height and width of the Schottky barrier at the interface between 2D metals and 2D semiconductors, leading to the realization of van der Waals rectifiers with enhanced performance.
Abstract: The applications of any two-dimensional (2D) semiconductor devices cannot bypass the control of metal-semiconductor interfaces, which can be severely affected by complex Fermi pinning effects and defect states. Here, we report a near-ideal rectifier in the all-2D Schottky junctions composed of the 2D metal 1 T′-MoTe2 and the semiconducting monolayer MoS2. We show that the van der Waals integration of the two 2D materials can efficiently address the severe Fermi pinning effect generated by conventional metals, leading to increased Schottky barrier height. Furthermore, by healing original atom-vacancies and reducing the intrinsic defect doping in MoS2, the Schottky barrier width can be effectively enlarged by 59%. The 1 T′-MoTe2/healed-MoS2 rectifier exhibits a near-unity ideality factor of ~1.6, a rectifying ratio of >5 × 105, and high external quantum efficiency exceeding 20%. Finally, we generalize the barrier optimization strategy to other Schottky junctions, defining an alternative solution to enhance the performance of 2D-material-based electronic devices. Here, a defect healing method is used to tune the height and width of the Schottky barrier at the interface between 2D metals and 2D semiconductors, leading to the realization of van der Waals rectifiers with enhanced performance.
60 citations
56 citations
54 citations
TL;DR: In this paper, a β-Ga2O3 HJBS diode with p-type NiOx was shown to achieve a low specific on-resistance (Ron,sp) of 1.94 mΩ cm2 with a breakdown voltage 1.34
Abstract: In this paper, we show that high-performance β-Ga2O3 hetero-junction barrier Schottky (HJBS) diodes with various β-Ga2O3 periodic fin widths of 1.5/3/5 μm are demonstrated with the incorporation of p-type NiOx. The β-Ga2O3 HJBS diode achieves a low specific on-resistance (Ron,sp) of 1.94 mΩ cm2 with a breakdown voltage of 1.34 kV at a β-Ga2O3 periodic fin width of 3 μm, translating to a direct-current Baliga's power figure of merit (PFOM) of 0.93 GW/cm2. In addition, we find that by shrinking the β-Ga2O3 width, the reverse leakage current is minimized due to the enhanced sidewall depletion effect from p-type NiOx. β-Ga2O3 HJBS diodes with p-type NiOx turn out to be an effective route for Ga2O3 power device technology by considering the high PFOM while maintaining a suppressed reverse leakage current.
53 citations
TL;DR: In this article, the authors present the first experimental demonstrations of large-area Ga2O3 Schottky barrier diodes (SBDs) packaged in the bottom-side-cooling and double-sidecooling configurations, and for the first time, characterizes the surge current capabilities of these packaged SBDs.
Abstract: Ultrawide-bandgap gallium oxide (Ga2O3) devices have recently emerged as promising candidates for power electronics; however, the low thermal conductivity ( k T) of Ga2O3 causes serious concerns about their electrothermal ruggedness. This letter presents the first experimental demonstrations of large-area Ga2O3 Schottky barrier diodes (SBDs) packaged in the bottom-side-cooling and double-side-cooling configurations, and for the first time, characterizes the surge current capabilities of these packaged Ga2O3 SBDs. Contrary to popular belief, Ga2O3 SBDs with proper packaging show high surge current capabilities. The double-side-cooled Ga2O3 SBDs with a 3 × 3-mm2 Schottky contact area can sustain a peak surge current over 60 A, with a ratio between the peak surge current and the rated current superior to that of similarly-rated commercial SiC SBDs. The key enabling mechanisms for this high surge current are the small temperature dependence of on -resistance, which strongly reduces the thermal runaway, and the double-side-cooled packaging, in which the heat is extracted directly from the Schottky junction and does not need to go through the low- k T bulk Ga2O3 chip. These results remove some crucial concerns regarding the electrothermal ruggedness of Ga2O3 power devices and manifest the significance of their die-level thermal management.
52 citations
TL;DR: In this article, the basic concepts, detection mechanism and evaluation parameters of Schottky junction-based photodetectors and the recent developments in the past five years are reviewed.
Abstract: In recent years, 2D layered materials have emerged as potential candidates in the opto-electronic field due to their intriguing optical, electrical and mechanical properties. Photodetectors based on 2D materials have been reported to exhibit excellent photodetection capability due to their tunable bandgap and ability to detect broadband spectrum ranging from UV to NIR. Schottky junction-based detectors are highly sensitive and fast responsive compared to other heterojunction devices. Schottky contacted devices are fabricated by constructing a heterojunction of a semiconductor with a metal or a metal-like material. In the case of 2D material-based photodetectors, either the semiconductor or the metal belongs to the 2D family. The detection properties of Schottky contacted devices are mainly dependent on the junction properties such as the barrier height. The photodetection performance of detectors with 2D materials is observed to be superior and further it can be enhanced by tuning the properties through various strategies. Herein, the basic concepts, detection mechanism and evaluation parameters of Schottky junction-based photodetectors and the recent developments in Schottky junction-based photodetectors achieved using various 2D materials in the past five years are reviewed. Emerging strategies to enhance the performance by adjusting the Schottky barrier height are elaborated. Finally, the summary and future prospects are provided.
TL;DR: In this paper, a novel one-dimensional-two-dimensional (1D-2D) CdIn2S4/carbon nanofibers/Co4S3 tandem Schottky heterojunction was synthesized by in-situ electrospinning combined with a hydrothermal method.
TL;DR: In this article, high performance β-Ga2O3 vertical heterojunction barrier Schottky (HJBS) diodes have been demonstrated together with the investigation of reverse leakage mechanisms.
Abstract: In this Letter, high-performance β-Ga2O3 vertical heterojunction barrier Schottky (HJBS) diodes have been demonstrated together with the investigation of reverse leakage mechanisms. In HJBS configurations, NiO/β-Ga2O3 p-n heterojunctions and p-NiO field limiting rings (FLRs) are implemented by using a reactive sputtering technique at room temperature without intentional etching damages. Determined from the temperature-dependent current-voltage characteristics, the reverse leakage mechanism of the HJBS diode is identified to be Poole-Frenkel emission through localized trap sates with an energy level of EC-0.72 eV. With an uniform FLR width/spacing of 2 μm in HJBS, a maximum breakdown voltage (BV) of 1.89 kV and a specific on-resistance (Ron,sp) of 7.7 mΩ·cm2 are achieved, yielding a high Baliga's figure-of-merit (FOM, BV2/Ron,sp) of 0.46 GW/cm2. The electric field simulation and statistical experimental facts indicate that the electric field crowding effect at device edges is greatly suppressed by the shrinkage of p-NiO FLR spacing, and the capability of sustaining high BV is enhanced by the NiO/β-Ga2O3 bipolar structure, both of which contribute to the improved device performance. This work makes a significant step to achieve high performance β-Ga2O3 power devices by implementing alternative bipolar structures to overcome the difficulty in p-type β-Ga2O3.
TL;DR: In this article, the avalanche and surge current ruggedness of the industry's first 1.2kV-class vertical GaN p-n diodes fabricated on 100mm GaN substrates was reported.
Abstract: This letter reports the avalanche and surge current ruggedness of the industry's first 1.2-kV-class vertical GaN p-n diodes fabricated on 100-mm GaN substrates. The 1.2-kV vertical GaN p-n diodes with a 1.39-mm2 device area and an avalanche breakdown voltage of 1589 V show a critical avalanche energy density of 7.6 J/cm2 in unclamped inductive switching tests, as well as a critical surge current of 54 A and a critical surge energy density of 180 J/cm2 in 10-ms surge current tests. All these values are the highest reported in vertical GaN devices and comparable to those of commercial SiC p-n diodes and merged p-n Schottky diodes. These GaN p-n diodes show significantly smaller reverse recovery compared to SiC p-n diodes, revealing less conductivity modulation in n-GaN. The negative temperature coefficient of differential on-resistance and the anticlockwise surge I–V locus are believed to be due to the increased acceptor ionization in p-GaN and the decreased contact resistance at high temperatures. These results suggest a high ruggedness of GaN p-n junctions with small bipolar currents and fast switching capabilities. As the first electrothermal ruggedness data for industry's vertical GaN devices, these results provide key new insights for the development of vertical GaN devices as well as their application spaces.
TL;DR: In this article, Schottky junctions between nanotubes (NTs) and FTO were fabricated by electrospinning SnO2NTs on FTO glass substrate, and the bias voltage was reduced to ∼176 V, which can effectively reduce energy consumption.
Abstract: One-dimensional metal-oxides (1D-MO) nanostructure has been regarded as one of the most promising candidates for high-performance photodetectors due to their outstanding electronic properties, low-cost and environmental stability However, the current bottlenecks are high energy consumption and relatively low sensitivity Here, Schottky junctions between nanotubes (NTs) and FTO were fabricated by electrospinning SnO2NTs on FTO glass substrate, and the bias voltage of SnO2NTs photodetectors was as low as ∼176 V, which can effectively reduce energy consumption Additionally, for improving the response and recovery speed of SnO2NTs photodetectors, the NTs were covered with organic/inorganic hybrid perovskite SnO2NTs/perovskite heterostructure photodetectors exhibit fast response/recovery speed (∼0075/004 s), and a wide optical response range (∼220-800 nm) At the same time, the bias voltage of heterostructure photodetectors was further reduced to 042 V The outstanding performance is mainly attributed to the formation of type-II heterojunctions between SnO2NTs and perovskite, which can facilitate the separation of photogenerated carriers, as well as Schottky junction between SnO2NTs and FTO, which reduce the bias voltage All the results indicate that the rational design of 1D-MO/perovskite heterostructure is a facile and efficient way to achieve high-performance photodetectors
TL;DR: In this paper, the authors construct ultrathin van der Waals heterostructures between graphene and a new 2D Janus MoGeSiN4 material and investigate their interfacial electronic properties and tunable Schottky barriers and contact types using first-principles calculations.
Abstract: Two-dimensional MoSi2N4 is an emerging class of 2D MA2N4 family, which has recently been synthesized in experiment. Herein, we construct ultrathin van der Waals heterostructures between graphene and a new 2D Janus MoGeSiN4 material and investigate their interfacial electronic properties and tunable Schottky barriers and contact types using first-principles calculations. The GR/MoGeSiN4 vdWHs are expected to be energetically favorable and stable. The high carrier mobility in graphene/MoGeSiN4 vdWHs makes them suitable for high-speed nanoelectronic devices. Furthermore, depending on the stacking patterns, either an n-type or a p-type Schottky contact is formed at the GR/MoGeSiN4 interface. The strain engineering and electric field can lead to the transformation from an n-type to a p-type Schottky contact or from Schottky to Ohmic contact in graphene/MoGeSiN4 heterostructure. These findings provide useful guidance for designing controllable Schottky nanodevices based on graphene/MoGeSiN4 heterostructures with high-performance.
TL;DR: In this article, the application of Bi with low HER activity as a robust cocatalyst for constructing Schottky-junction photocatalysts toward N2 reduction to ammonia is reported.
Abstract: Solar-powered N2 reduction in aqueous solution is becoming a research hotspot for ammonia production. Schottky junctions at the metal/semiconductor interface have been effective to build up a one-way channel for the delivery of photogenerated electrons toward photoredox reactions. However, their applications for enhancing the aqueous phase reduction of N2 to ammonia have been bottlenecked by the difficulty of N2 activation and the competing H2 evolution reaction (HER) at the metal surface. Herein, the application of Bi with low HER activity as a robust cocatalyst for constructing Schottky-junction photocatalysts toward N2 reduction to ammonia is reported. The introduction of Bi not only boosts the interfacial electron transfer from excited photocatalysts due to the built-in Schottky-junction effect at the Bi/semiconductor interface but also synchronously facilitates the on-site N2 adsorption and activation toward solar ammonia production. The unidirectional charge transfer to the active site of Bi significantly promotes the photocatalytic N2-to-ammonia conversion efficiency by 65 times for BiOBr. In addition, utilizing Bi to enhance the photocatalytic ammonia production can be extended to other semiconductor systems. This work is expected to unlock the promise of engineering Schottky junctions toward high-efficiency solar N2-to-ammonia conversion in aqueous phase.
05 Nov 2021
TL;DR: In this paper, the Schottky device based on carbon dots (CDots) decorated magnesium oxide (MgO) nano-particles has been engineered for H2S gas sensing applications.
Abstract: Schottky device based on carbon dots (CDots) decorated magnesium oxide (MgO) nano-particles (CDots@MgO) has been engineered for H2S gas sensing applications. TEM microscope proves the decoration of CDots on the surface of MgO nano-particles. The sensor device has been tested for various reducing gases. However, CDots@MgO device displays high response against H2S gas, as a resultof reducing the barrier height between CDots@MgO crystals. I–V behavior of the engineered sensor device is examined under both open air and H2S gas environments. The parameters (series resistance Rs, effective barrier height ϕ B , and ideality factor n) of the schottky diode are determined for the CDots@MgO and MgO based sensors. Interestingly, under the exposure of 120 ppm of H2S, CDots@MgO sensor has shown response current value 11 times higher than MgO sensor at external biasing voltage = −0.7 V. The reduction of barrier height can be observed with increasing the (Tapplied) up to 200 °C and then increases. The obtained results prove that both device response and sensitivity are strongly influenced by the change in the barrier height. Finally, this effort introduces an invaluable methodology aiming at sensing the harmful gases by engineering a new gas sensor based on Schottky device of metal oxides decorated with CDots for high response, low power-consumption, high repeatability and high stability.
TL;DR: In this article, the Schottky heterostructure between cobalt-iron hydroxide and MXene and surface electron density modification with phosphorus doping provide an efficient method to solve the crucial issues.
Abstract: The development of non-precious metal electrocatalysts to synergistically expose more active sites and optimize intrinsic activity still remains a huge challenge. Transition metal layered double hydroxide (LDH) has a great potential in electrocatalysis due to its unique sheet-like nanostructure and low cost. However, the poor electrical conductivity and sluggish water dissociation process hinder their development. Herein, the interface effect of Schottky heterostructure between cobalt-iron hydroxide and MXene and surface electron density modification with phosphorus (P) doping provide an efficient method to solve these crucial issues. The novel Schottky heterostructure catalyst (P-CoFe-LDH@MXene/NF) with self-driven charge transfer can enhance electron transport efficiency. In addition, the surface electron density optimized by P-doping will promote the ability of H+/OH- ion adsorption and redox reaction for overall water splitting. The as-prepared P-CoFe-LDH@MXene/NF requires overpotentials of only 85 mV at 10 mA cm−2 for HER and 252 mV at 200 mA cm−2 for OER in 1.0 M KOH, respectively. And under an alkaline electrolyzer, it can be driven 10 mA cm−2 at a low voltage of 1.52 V for overall water splitting with remarkable durability for 100 h. More broadly, this design concept is universal and it can be extended to design other transition metal-based catalysts.
TL;DR: In this article, a quasi-vertical GaN junction barrier Schottky diode on a low-cost sapphire substrate was reported, achieving a reverse leakage in level of 10−7 A/cm2, as well as a high on/off current ratio of 1010 and a high breakdown voltage of 838 V.
Abstract: In this letter, we report a quasi-vertical GaN junction barrier Schottky diode on low-cost sapphire substrate. With the high quality GaN epitaxy and selective-area p-islands formed via Magnesium ion implantation at the anode region, reverse leakage in level of 10−7 A/cm2 was achieved, as well as a high on/off current ratio of 1010 and a high breakdown voltage of 838 V. Meanwhile, advantageous characteristics as expected in vertical GaN Schottky barrier diode were realized, including a low turn-on voltage of 0.5 V and fast switching performance under 400 V/10 A operation condition. Along with the improved heat dissipation via substrate thinning and packaging techniques, the diode retains a relatively low thermal resistance, enabling high current rectification level over 60 A, power efficiency up to 98.7 %, while maintaining low case temperatures.
TL;DR: In this paper, a single equation is proposed to describe the currentvoltage characteristics of two-terminal semiconductor devices with Schottky contacts, which can be used to estimate the Schotty barrier height and the ideality factor.
Abstract: Schottky barriers are often formed at the semiconductor/metal contacts and affect the electrical behaviour of semiconductor devices. In particular, Schottky barriers have been playing a major role in the investigation of the electrical properties of mono and two-dimensional nanostructured materials, although their impact on the current-voltage characteristics has been frequently neglected or misunderstood. In this work, we propose a single equation to describe the current-voltage characteristics of two-terminal semiconductor devices with Schottky contacts. We apply the equation to numerically simulate the electrical behaviour for both ideal and non-ideal Schottky barriers. The proposed model can be used to directly estimate the Schottky barrier height and the ideality factor. We apply it to perfectly reproduce the experimental current-voltage characteristics of ultrathin molybdenum disulphide or tungsten diselenide nanosheets and tungsten disulphide nanotubes. The model constitutes a useful tool for the analysis and the extraction of relevant transport parameters in any two-terminal device with Schottky contacts.
TL;DR: In this article, a multi-layer perceptron, a feed-forward back-propagation artificial neural network was developed using 362 experimental data obtained, where temperature (T) and voltage (V) values were selected as input variables and the hidden layer has 15 neurons, the current (I) value was obtained as output.
Abstract: Shottky diodes are one of the important components of electronic systems. Therefore, it is very important to determine the parameters of the diodes according to the area in which they will be used. One of the most important of these parameters is the current-voltage characteristic of the diode. In this study, firstly, current values of the Schottky diode in the voltage range of −2 V to +3 V are experimentally measured in the temperature range of 100–300 K. In order to estimate the current-voltage characteristic of Shottky diode at different temperatures, a multi-layer perceptron, a feed-forward back-propagation artificial neural network was developed using 362 experimental data obtained. In the artificial neural network where temperature (T) and voltage (V) values are selected as input variables and the hidden layer has 15 neurons, the current (I) value is obtained as output. The results obtained from the artificial neural network have been found to be in good agreement with the experimental data of the Schottky diode.
TL;DR: In this article, the authors demonstrate scaled-up GaN-on-Si tri-Anode Schottky barrier diodes (SBDs), whose excellent dc and switching performance are compared to commercial Si fast-recovery dioders and SiC SBDs.
Abstract: Gallium nitride (GaN) transistors are being employed in an increasing number of applications thanks to their excellent performance and competitive price. Yet, GaN diodes are not commercially available, and little is known about their performance and potential impact on power circuit design. In this article, we demonstrate scaled-up GaN-on-Si Tri-Anode Schottky barrier diodes (SBDs), whose excellent dc and switching performance are compared to commercial Si fast-recovery diodes and SiC SBDs. Moreover, the advantageous lateral GaN-on-Si architecture enables the integration of several devices on the same chip, paving the way for power integrated circuits (ICs). This is demonstrated by realizing a diode-multiplier IC, which includes up to eight monolithically integrated SBDs on the same chip. The IC was integrated on a dc–dc magnetic-less boost converter able to operate at a frequency of 1 MHz. The IC performance and footprint are compared to the same circuit realized with discrete Si and SiC vertical devices, showing the potential of GaN power ICs for efficient and compact power converters.
TL;DR: In this paper, a quasi-vertical GaN Schottky barrier diode (SBD) was successfully fabricated by using a high-quality n−-GaN drift layer with a precisely-controlled n-type doping.
Abstract: A high-performance quasi-vertical GaN Schottky barrier diode (SBD) was successfully fabricated by using a high-quality n−-GaN drift layer with a precisely-controlled n-type doping. A high current on/off ratio of 1010, an ideality factor of 1.03, a low specific on-resistance of 1.41 $\text{m}\Omega \cdot $ cm2, and a relatively high breakdown voltage (BV) of 250 V have been achieved for the SBD without edge termination. Furthermore, with an Argon-implanted termination, the as-fabricated GaN-on-Si SBD shows a record high BV of 405 V, yielding a critical electric field of ~ 2 MV/cm, while the forward conduction characteristics are well maintained.
TL;DR: In this paper, the ultrafast reverse recovery β -Ga2O3 Schottky barrier diode (SBD) with improved breakdown voltage is proposed and investigated experimentally, which features the compound termination, consisting of air space field plate and thermal oxidation terminal.
Abstract: In this letter, the ultrafast reverse recovery β -Ga2O3 Schottky barrier diode (SBD) with improved breakdown voltage is proposed and investigated experimentally It features the compound termination, consisting of air space field plate and thermal oxidation terminal The compound termination not only reduces high-density interface states at the dielectric/Ga2O3 interface and the electron concentration in the oxidation terminal, but also modulates the electric-field distribution and suppresses the peak electric-field at the bottom of anode Therefore, the reverse leakage current is suppressed as well as the reverse recovery and breakdown characteristics are improved effectively The Ga2O3 SBDs with the diameter of 1000 μm obtain ultrashort reverse recovery time of 75 ns and ultralow reverse recovery charge of 10 nC at di / dt = 50 A/μs with its breakdown voltage up to 400 V, maintaining good rectification characteristics The temperature-dependences of both forward conduction and reverse recovery characteristics are discussed in temperature range from 300 to 500 K The results prove that the superior electronics performance of the β -Ga2O3 SBDs with good electronics thermal tolerance can overcome the low thermal conductivity of β -Ga2O3 to a certain extent The fabricated β -Ga2O3 SBDs have great potential for high power and high-frequency applications
TL;DR: In this paper, a comprehensive review summarizes the current progress, understanding, and challenges in vertical GaN power devices, which can serve as not only a gateway for those interested in the field but also a critical reference for researchers in the wide bandgap semiconductor and power electronics community.
Abstract: Vertical gallium nitride (GaN) power devices are enabling next-generation power electronic devices and systems with higher energy efficiency, higher power density, faster switching, and smaller form factor. In Part I of this review, we have reviewed the basic design principles and physics of building blocks of vertical GaN power devices, i.e., Schottky barrier diodes and p-n diodes. Key topics such as materials engineering, device engineering, avalanche breakdown, and leakage mechanisms are discussed. In Part II of this review, several more advanced power rectifiers are discussed, including junction barrier Schottky (JBS) rectifiers, merged p-n/Schottky (MPS) rectifiers, and trench metal–insulator–semiconductor barrier Schottky (TMBS) rectifiers. Normally- OFF GaN power transistors have been realized in various advanced device structures, including current aperture vertical electron transistors (CAVETs), junction field-effect transistors (JFETs), metal–oxide–semiconductor field-effect transistors (MOSFETs), and fin field-effect transistors (FinFETs). A detailed analysis on their performance metrics is provided, with special emphasis on the impacts of key fabrication processes such as etching, ion implantation, and surface treatment. Lastly, exciting progress has been made on selective area doping and regrowth, a critical process for the fabrication of vertical GaN power devices. Various materials characterization techniques and surface treatments have proven to be beneficial in aiding this rapid development. This timely and comprehensive review summarizes the current progress, understanding, and challenges in vertical GaN power devices, which can serve as not only a gateway for those interested in the field but also a critical reference for researchers in the wide bandgap semiconductor and power electronics community.
TL;DR: The Mott-Schottky heterojunction formed at the interface of ultrafine metallic Ni and semiconducting V2 O3 nanoparticles is constructed, and the heterojunctions are "knitted" into the tulle-like monolayer nanosheets on nickel foam (NF) as discussed by the authors.
Abstract: The Mott-Schottky heterojunction formed at the interface of ultrafine metallic Ni and semiconducting V2 O3 nanoparticles is constructed, and the heterojunctions are "knitted" into the tulle-like monolayer nanosheets on nickel foam (NF). The greatly reduced particle sizes of both Ni and V2 O3 on the Mott-Schottky heterojunction highly enhance the number of Schottky heterojunctions per unit area of the materials. Moreover, arranging the heterojunctions into the monolayer nanosheets makes the heterojunctions repeat and expose to the electrolyte sufficiently. The Schottky heterojunctions are like countless self-powered charge transfer workstations embedded in the tulle-like monolayer nanosheets, promoting maximum of the materials to participate into the electron transfer and become catalytic active sites. In addition, the tulle-like monolayer nanosheet structure can assist in pumping liquid phase electrolyte to the surface of catalysts, owing to the capillary force. The V2 O3 /Ni/NF Mott-Schottky catalyst exhibits excellent hydrogen evolution reaction (HER) performance with a low η10 of 54 mV and needs -107 mV to get the current density of -100 mA cm-2 . Furthermore, V2 O3 /Ni/NF Schottky electrocatalyst exhibits excellent urea oxidation reaction activity: 1.40, 1.51, and 1.61 V versus reversible hydrogen electrode (RHE) voltage are required to reach a current density of 100, 500, and 1000 mA cm-2 , respectively.