Binary group III-nitride based heterostructures: band offsets and transport properties
TL;DR: In this paper, the growth of non-polar III-nitrides has been an important subject due to its potential improvement on the efficiency of III-nodes-based opto-electronic devices.
Abstract: In the last few years, there has been remarkable progress in the development of group III-nitride based materials because of their potential application in fabricating various optoelectronic devices such as light emitting diodes, laser diodes, tandem solar cells and field effect transistors. In order to realize these devices, growth of device quality heterostructures are required. One of the most interesting properties of a semiconductor heterostructure interface is its Schottky barrier height, which is a measure of the mismatch of the energy levels for the majority carriers across the heterojunction interface. Recently, the growth of non-polar III-nitrides has been an important subject due to its potential improvement on the efficiency of III-nitride-based opto-electronic devices. It is well known that the c-axis oriented optoelectronic devices are strongly affected by the intrinsic spontaneous and piezoelectric polarization fields, which results in the low electron-hole recombination efficiency. One of the useful approaches for eliminating the piezoelectric polarization effects is to fabricate nitride-based devices along non-polar and semi-polar directions. Heterostructures grown on these orientations are receiving a lot of focus due to enhanced behaviour. In the present review article discussion has been carried out on the growth of III-nitride binary alloys and properties of GaN/Si, InN/Si, polar InN/GaN, and nonpolar InN/GaN heterostructures followed by studies on band offsets of III-nitride semiconductor heterostructures using the x-ray photoelectron spectroscopy technique. Current transport mechanisms of these heterostructures are also discussed.
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01 Mar 1997
TL;DR: In this article, first principles electronic structure calculations on wurtzite AlN, GaN, and InN reveal crystal field splitting parameters ΔCF of −217, 42, and 41 meV, respectively.
Abstract: First‐principles electronic structure calculations on wurtzite AlN, GaN, and InN reveal crystal‐field splitting parameters ΔCF of −217, 42, and 41 meV, respectively, and spin–orbit splitting parameters Δ0 of 19, 13, and 1 meV, respectively. In the zinc blende structure ΔCF≡0 and Δ0 are 19, 15, and 6 meV, respectively. The unstrained AlN/GaN, GaN/InN, and AlN/InN valence band offsets for the wurtzite (zinc blende) materials are 0.81 (0.84), 0.48 (0.26), and 1.25 (1.04) eV, respectively. The trends in these spectroscopic quantities are discussed and recent experimental findings are analyzed in light of these predictions.
268 citations
TL;DR: In this article, a novel nanowire structure adopting a graded-index separate confinement heterostructure (GRINSCH) in which the active region is sandwiched between two compositionally graded AlGaN layers, namely, a GRINSCH diode, is proposed.
Abstract: High-density dislocations in materials and poor electrical conductivity of p-type AlGaN layers constrain the performance of the ultraviolet light emitting diodes and lasers at shorter wavelengths. To address those technical challenges, we design, grow, and fabricate a novel nanowire structure adopting a graded-index separate confinement heterostructure (GRINSCH) in which the active region is sandwiched between two compositionally graded AlGaN layers, namely, a GRINSCH diode. Calculated electronic band diagram and carrier concentrations show an automatic formation of a p–n junction with electron and hole concentrations of ∼1018 /cm3 in the graded AlGaN layers without intentional doping. The transmission electron microscopy experiment confirms the composition variation in the axial direction of the graded AlGaN nanowires. Significantly lower turn-on voltage of 6.5 V (reduced by 2.5 V) and smaller series resistance of 16.7 Ω (reduced by nearly four times) are achieved in the GRINSCH diode, compared with the ...
32 citations
TL;DR: In this article, the InGaN nanowires (NWs) were grown on a metallic Ti/Si template for improving the water splitting performance compared to a bare Si substrate, and the open circuit potential of the epitaxially grown NWs on metallic Ti was almost two times higher than when directly grown on the Si substrate.
Abstract: Water splitting using InGaN-based photocatalysts may make a great contribution to future renewable energy production systems. Among the most important parameters that need to be optimized are those related to substrate lattice-matching compatibility. Here, we directly grow InGaN nanowires (NWs) on a metallic Ti/Si template, for improving the water splitting performance compared to a bare Si substrate. The open circuit potential of the epitaxially grown InGaN NWs on metallic Ti was almost two times higher than when directly grown on the Si substrate. The interfacial transfer resistance was also reduced significantly after introducing the metallic Ti interlayer. An applied-bias-photon-to-current conversion efficiency of 2.2% and almost unity faradaic efficiency for hydrogen generation were achieved using this approach. The InGaN NWs grown on Ti showed improved stability for hydrogen generation under continuous operation conditions, when compared to those grown on Si, emphasizing the role of the semiconductor-on-metal approach in enhancing the overall efficiency of water splitting devices.
31 citations
TL;DR: In this paper, the authors provide an overview of aluminum nitride, sapphire, and gallium oxide as platforms for deep-ultraviolet optoelectronic devices, in which they criticize the status of sarspphire as a platform for efficient deep UV devices and detail advancements in device growth and fabrication.
Abstract: Progress in the design and fabrication of ultraviolet and deep-ultraviolet group III–nitride optoelectronic devices, based on aluminum gallium nitride and boron nitride and their alloys, and the heterogeneous integration with two-dimensional and oxide-based materials is reviewed. We emphasize wide-bandgap nitride compound semiconductors (i.e., (B, Al, Ga)N) as the deep-ultraviolet materials of interest, and two-dimensional materials, namely graphene, two-dimensional boron nitride, and two-dimensional transition metal dichalcogenides, along with gallium oxide, as the hybrid integrated materials. We examine their crystallographic properties and elaborate on the challenges that hinder the realization of efficient and reliable ultraviolet and deep-ultraviolet devices. In this article we provide an overview of aluminum nitride, sapphire, and gallium oxide as platforms for deep-ultraviolet optoelectronic devices, in which we criticize the status of sapphire as a platform for efficient deep-ultraviolet devices and detail advancements in device growth and fabrication on aluminum nitride and gallium oxide substrates. A critical review of the current status of deep-ultraviolet light emission and detection materials and devices is provided.
30 citations
TL;DR: In this paper, the impact of biaxial strain and an external electric field on the electronic and optical properties of two-dimensional PbI2/α-Te van der Waals (vdW) heterostructures was systematically studied.
Abstract: Using density functional theory (DFT), we systematically studied the impact of biaxial strain and an external electric field on the electronic and optical properties of two-dimensional PbI2/α-Te van der Waals (vdW) heterostructures. The stability of the constructed PbI2/α-Te heterostructures has been predicted based on the binding energy, phonon spectrum, and molecular dynamics simulation. Our results have revealed that the most stable PbI2/α-Te vdW heterostructure has a distinct type-I band alignment with an indirect bandgap of 0.64 eV. The intrinsic type-I band alignment can be transformed to either type-II or type-III by applying a strong external electric field, which holds great potential for designing multifunctional devices. Furthermore, the compressive and tensile strains can be varied to effectively tune the bandgap value between 0.55 eV and 0.85 eV. Additionally, the constructed PbI2/α-Te vdW heterostructure exhibits excellent optical absorption properties in the UV–Vis regions under biaxial strain and external electric field. Overall, the constructed PbI2/α-Te heterostructure is expected to find potential applications in nanoelectronic devices.
28 citations
References
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21 Mar 1997
TL;DR: The physics of gallium nitrides and related compounds GaN growth p-Type GaN obtained by electron beam irradiation n-Type GAN p-type GaN InGaN Zn and Si co-doped GaN double-heterostructure blue and blue green LEDs inGaN single-quantum-well structure LEDs room-temperature pulsed operation of laser diodes emission mechanisms of LEDs and LDs room temperature CW operation of InGAN MQW LDs latest results as discussed by the authors.
Abstract: Physics of gallium nitrides and related compounds GaN growth p-Type GaN obtained by electron beam irradiation n-Type GaN p-Type GaN InGaN Zn and Si co-doped InGaN/AlGaN double-heterostructure blue and blue-green LEDs inGaN single-quantum-well structure LEDs room-temperature pulsed operation of laser diodes emission mechanisms of LEDs and LDs room temperature CW operation of InGaN MQW LDs latest results - lasers with self-organized InGaN quantum dots
3,794 citations
TL;DR: In this article, the InGaN multi-quantum-well (MQW) structure was used for laser diodes, which produced 215mW at a forward current of 2.3
Abstract: InGaN multi-quantum-well (MQW) structure laser diodes (LDs) fabricated from III-V nitride materials were grown by metalorganic chemical vapor deposition on sapphire substrates. The mirror facet for a laser cavity was formed by etching of III-V nitride films without cleaving. As an active layer, the InGaN MQW structure was used. The InGaN MQW LDs produced 215 mW at a forward current of 2.3 A, with a sharp peak of light output at 417 nm that had a full width at half-maximum of 1.6 nm under the pulsed current injection at room temperature. The laser threshold current density was 4 kA/cm2. The emission wavelength is the shortest one ever generated by a semiconductor laser diode.
2,029 citations
TL;DR: In this paper, the Schottky barrier heights and band offsets for high dielectric constant oxides on Pt and Si were calculated and good agreement with experiment is found for barrier heights.
Abstract: Wide-band-gap oxides such as SrTiO3 are shown to be critical tests of theories of Schottky barrier heights based on metal-induced gap states and charge neutrality levels. This theory is reviewed and used to calculate the Schottky barrier heights and band offsets for many important high dielectric constant oxides on Pt and Si. Good agreement with experiment is found for barrier heights. The band offsets for electrons on Si are found to be small for many key oxides such as SrTiO3 and Ta2O5 which limit their utility as gate oxides in future silicon field effect transistors. The calculations are extended to screen other proposed oxides such as BaZrO3. ZrO2, HfO2, La2O3, Y2O3, HfSiO4, and ZrSiO4. Predictions are also given for barrier heights of the ferroelectric oxides Pb1−xZrxTiO3 and SrBi2Ta2O9 which are used in nonvolatile memories.
1,848 citations
PARC1
TL;DR: In this article, the group III elements of the semiconducting nitrides have been used for the fabrication of high-efficiency solid-state devices that emit green and blue light.
Abstract: Recent advances in fabrication technologies for the semiconducting nitrides of the group III elements have led to commercially available, high-efficiency solid-state devices that emit green and blue light Light-emitting diodes based on these materials should find applications in flat-panel displays, and blue and ultraviolet laser diodes promise high-density optical data storage and high-resolution printing
1,450 citations