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Showing papers on "p–n junction published in 2013"


Journal ArticleDOI
TL;DR: The photoelectrochemical measurement shows that the p-MoS2/n-rGO junction greatly enhances the charge generation and suppresses the charge recombination, which is responsible for enhancement of solar hydrogen generation.
Abstract: Molybdenum disulfide (MoS2) is a promising candidate for solar hydrogen generation but it alone has negligible photocatalytic activity. In this work, 5–20 nm sized p-type MoS2 nanoplatelets are deposited on the n-type nitrogen-doped reduced graphene oxide (n-rGO) nanosheets to form multiple nanoscale p–n junctions in each rGO nanosheet. The p-MoS2/n-rGO heterostructure shows significant photocatalytic activity toward the hydrogen evolution reaction (HER) in the wavelength range from the ultraviolet light through the near-infrared light. The photoelectrochemical measurement shows that the p-MoS2/n-rGO junction greatly enhances the charge generation and suppresses the charge recombination, which is responsible for enhancement of solar hydrogen generation. The p-MoS2/n-rGO is an earth-abundant and environmentally benign photocatalyst for solar hydrogen generation.

579 citations


Journal ArticleDOI
TL;DR: In this article, a p-n junction Cu2O/BiVO4 heterogeneous nanostructures for enhancement of visible-light photocatalytic properties of BiVO4 nanocrystals have been successfully prepared through coupling a hydrothermal process with polyol strategy.
Abstract: p–n junction Cu2O/BiVO4 heterogeneous nanostructures for enhancement of visible-light photocatalytic properties of BiVO4 nanocrystals have been successfully prepared through coupling a hydrothermal process with polyol strategy. The assembly of p-type Cu2O nanoparticles produces a large number of nano p–n junction heterostructures on the surface of the BiVO4 nanocrystals, where Cu2O and BiVO4 form p- and n-type semiconductors, respectively. The experimental results reveal that these p–n junction Cu2O/BiVO4 heterogeneous nanostructures exhibit much higher visible-light photocatalytic activities than the individual BiVO4 nanocrystals for the degradation of model dyes methylene blue and colorless organic phenol under visible light irradiation. The enhanced photocatalytic efficiencies are attributed to the charge transfer from n-type BiVO4 to the attached p-type Cu2O nanoparticles, which effectively reduces the recombination of electrons and holes, leading to the enhancement of the photocatalytic properties of the heterostructure nanostructures. These new p–n junction heteronanostructures are expected to show considerable potential applications in solar-driven wastewater treatment.

264 citations


Journal ArticleDOI
TL;DR: A method that electronically controls and locates p-n junctions in liquid-gated ambipolar MoS2 transistors and formed a bias-independent p- n junction, which could perform a crucial role in the development of optoelectronic valleytronic devices.
Abstract: Molybdenum disulfide (MoS2) has gained attention because of its high mobility and circular dichroism. As a crucial step to merge these advantages into a single device, we present a method that electronically controls and locates p-n junctions in liquid-gated ambipolar MoS2 transistors. A bias-independent p-n junction was formed, and it displayed rectifying I-V characteristics. This p-n diode could perform a crucial role in the development of optoelectronic valleytronic devices.

220 citations


Journal ArticleDOI
Marcus Freitag1, Tony Low1, Phaedon Avouris1
TL;DR: This work investigates the role of the substrate in providing cooling pathways for photoexcited carriers under ambient conditions by partially suspending few-layer graphene over a trench and finds the photocurrent in suspended p-n junctions to be an order of magnitude larger than in supported structures.
Abstract: The responsivity of graphene photodetectors depends critically on the elevated temperature of the electronic subsystem upon photoexcitation. We investigate the role of the substrate in providing cooling pathways for photoexcited carriers under ambient conditions by partially suspending few-layer graphene over a trench. Through photocurrent microscopy, we observe p–n junctions near the supported/suspended interfaces that produce photothermoelectric currents. Most importantly, we find the photocurrent in suspended p–n junctions to be an order of magnitude larger than in supported structures. This enhancement is attributed to the elimination of a dominant electronic cooling channel via the surface phonons of the polar substrate. Our work documents this mechanism of energy exchange between graphene and its environment, and it points to the importance of dielectric engineering for future improved graphene photodetectors.

196 citations


Journal ArticleDOI
Yeonwoong Jung1, Xiaokai Li1, Nitin K. Rajan1, André D. Taylor1, Mark A. Reed1 
TL;DR: This study suggests that these hybrid solar cells operate in the same manner as single crystalline p-n homojunction Si solar cells.
Abstract: Carrier transport characteristics in high-efficiency single-walled carbon nanotubes (SWNTs)/silicon (Si) hybrid solar cells are presented. The solar cells were fabricated by depositing intrinsic p-type SWNT thin-films on n-type Si wafers without involving any high-temperature process for p–n junction formation. The optimized cells showed a device ideality factor close to unity and a record-high power-conversion-efficiency of >11%. By investigating the dark forward current density characteristics with varying temperature, we have identified that the temperature-dependent current rectification originates from the thermally activated band-to-band transition of carriers in Si, and the role of the SWNT thin films is to establish a built-in potential for carrier separation/collection. We have also established that the dominant carrier transport mechanism is diffusion, with minimal interface recombination. This is further supported by the observation of a long minority carrier lifetime of ∼34 μs, determined by t...

196 citations


Journal ArticleDOI
TL;DR: In this article, the characteristics of Gallium Nitride (GaN) p-n junction diodes fabricated on free-standing GaN substrates with low specific on-resistance Ron and high breakdown voltage VB were described.
Abstract: In this letter, we describe the characteristics of Gallium Nitride (GaN) p–n junction diodes fabricated on free-standing GaN substrates with low specific on-resistance Ron and high breakdown voltage VB. The breakdown voltage of the diodes with the field-plate (FP) structure was over 3 kV, and the leakage current was low, i.e., in the range of 10-4 A/cm2. The specific on-resistance of the diodes of 60 µm diameter with the FP structure was 0.9 mΩcm2. Baliga's figure of merit (VB2/Ron) of 10 GW/cm2 is obtained. Although a certain number of dislocations were included in the device, these excellent results indicated a definite availability of this material system for power-device applications.

98 citations


Journal ArticleDOI
TL;DR: If catalyst-free III-nitride nanowires are to be used to form polarization-doped heterostructures, then it is imperative to understand their mixed polarity and to design devices using thesenanowires accordingly.
Abstract: Polarization-induced nanowire light emitting diodes (PINLEDs) are fabricated by grading the Al composition along the c-direction of AlGaN nanowires grown on Si substrates by plasma-assisted molecular beam epitaxy (PAMBE). Polarization-induced charge develops with a sign that depends on the direction of the Al composition gradient with respect to the [0001] direction. By grading from GaN to AlN then back to GaN, a polarization-induced p–n junction is formed. The orientation of the p-type and n-type sections depends on the material polarity of the nanowire (i.e., Ga-face or N-face). Ga-face material results in an n-type base and a p-type top, while N-face results in the opposite. The present work examines the polarity of catalyst-free nanowires using multiple methods: scanning transmission electron microscopy (STEM), selective etching, conductive atomic force microscopy (C-AFM), and electroluminescence (EL) spectroscopy. Selective etching and STEM measurements taken in annular bright field (ABF) mode demons...

93 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed a process to fabricate suspended graphene devices with local bottom gates, and tested it by realizing electrostatically controlled pn junctions on a suspended graphene mono-layer nearly 2'μm long, which exhibited characteristic Fabry-Perot oscillations in the cavities formed by the pn junction and each of the contacts.
Abstract: We have developed a process to fabricate suspended graphene devices with local bottom gates, and tested it by realizing electrostatically controlled pn junctions on a suspended graphene mono-layer nearly 2 μm long. Measurements as a function of gate voltage, magnetic field, bias, and temperature exhibit characteristic Fabry-Perot oscillations in the cavities formed by the pn junction and each of the contacts, with transport occurring in ballistic regime. Our results demonstrate the possibility to achieve a high degree of control on the local electronic properties of ultra-clean suspended graphene layers, a key aspect for the realization of high quality graphene nanostructures.

90 citations


Journal ArticleDOI
TL;DR: In this article, a simple and effective approach to enhance the piezoelectric output performance of the ZnO NGs by forming a CuO-ZnO heterostructure was reported.
Abstract: The piezoelectric potential screening by large excess electrons in nominally undoped ZnO has limited the energy conversion efficiency of the ZnO nanogenerators (NGs). In this study, we report a simple and effective approach to enhance the piezoelectric output performance of the ZnO NGs by forming a CuO–ZnO heterostructure. By depositing a ZnO thin film on the pre-deposited CuO thin film, which forms a p–n junction, excess electrons in ZnO can be effectively reduced. Thus, the piezoelectric potential generated in ZnO by an applied force can be less affected. Using this approach, we obtained an output voltage up to ∼7.5 V and a maximum current of 4.5 μA cm−2 measured under the forward connection, which is a 7-fold higher output voltage and an approximately one order of magnitude higher current density by comparison to the ZnO NGs without a CuO layer. Our results clearly demonstrate the effectiveness of a CuO–ZnO heterostructure for realizing high performance flexible energy harvesting devices.

69 citations


Journal ArticleDOI
20 Feb 2013-Langmuir
TL;DR: It is demonstrated that the multiple-pn-junction structure is favorable to enhancing the photocurrent density and the onset potential of the photoelectrode and the carrier transfer inside the photoElectrode is improved by narrowing the single-layer thickness.
Abstract: Nanomultiple CaFe2O4/ZnFe2O4pn junctions are prepared by a pulsed laser deposition method to explore their photoelectrochemical properties as the photoelectrodes. It is demonstrated that the multiple-pn-junction structure is favorable to enhancing the photocurrent density and the onset potential of the photoelectrode. Furthermore, the 20-junction photoelectrode-based PEC cell yields a high open circuit photovoltage of up to 0.97 V, which is much higher than that for a single pn junction photoelectrode PEC cell that yields an open circuit photovoltage of 0.13 V. A multiple-junction band structure model is assumed to describe the behavior of the CaFe2O4/ZnFe2O4 multiple-junction photoelectrodes. It is suggested that the open circuit photovoltage is dominated by the number of pn junctions in a multiple-junction photoelectrode and the carrier transfer inside the photoelectrode is improved by narrowing the single-layer thickness. These findings provide a new approach to designing the multiple-junction structur...

68 citations


Journal ArticleDOI
TL;DR: In this article, high quality Bi2Te3 and Sb2Te 3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy.
Abstract: High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, X-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111) substrate is better than a vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3 topological insulator films can be directly grown on a GaAs (111) substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.

Journal ArticleDOI
TL;DR: In this article, an extremely large magnetoresistance effect on silicon-based p-n junction with vertical geometry over a wide range of temperatures and magnetic fi elds is reported.
Abstract: The fi nding of an extremely large magnetoresistance effect on silicon based p–n junction with vertical geometry over a wide range of temperatures and magnetic fi elds is reported. A 2500% magnetoresistance ratio of the Si p–n junction is observed at room temperature with a magnetic fi eld of 5 T and the applied bias voltage of only 6 V, while a magnetoresistance ratio of 25 000% is achieved at 100 K. The current-voltage ( I–V ) behaviors under various external magnetic fi elds obey an exponential relationship, and the magnetoresistance effect is signifi cantly enhanced by both contributions of the electric fi eld inhomogeneity and carrier concentrations variation. Theoretical analysis using classical p–n junction transport equation is adapted to describe the I–V curves of the p–n junction at different magnetic fi elds and reveals that the large magnetoresistance effect origins from a change of space-charge region in the p–n junction induced by external magnetic fi eld. The results indicate that the conventional p–n junction is proposed to be used as a multifunctional material based on the interplay between electronic and magnetic response, which is signifi cant for future magneto-electronics in the semiconductor industry.

Journal ArticleDOI
TL;DR: In this paper, the forward voltage characteristics of GaInN light-emitting diodes are studied in the temperature range of 80 K to 450‰K, and it is shown that both p-type contact and sheet resistance decrease drastically with increasing temperature.
Abstract: The forward voltage characteristics of GaInN light-emitting diodes are studied in the temperature range of 80 K to 450 K. The forward-voltage-vs.-temperature curve has a “two-slope” characteristic with a slope of dVf/dT = −1.7 mV/K and −8.0 mV/K at room temperature and cryogenic temperatures, respectively. To investigate the two-slope characteristic, we perform transmission-line-model measurements on p-type GaN and show that both p-type contact and sheet resistance decrease drastically with increasing temperature. We conclude that dVf/dT in the high-slope region is limited by p-type sheet and contact resistance, and in the low-slope region by the GaN pn junction properties.

Patent
23 Jan 2013
TL;DR: A steering device is a serially coupled to a resistive switching device to provide rectification for the resistive switch device to form a nonvolatile memory device as mentioned in this paper, where the steering device includes an n-type impurity region comprising a zinc oxide material and a p type impurity regions comprising a silicon germanium material.
Abstract: A steering device. The steering device includes an n-type impurity region comprising a zinc oxide material and a p-type impurity region comprising a silicon germanium material. A pn junction region formed from the zinc oxide material and the silicon germanium material. The steering device is a serially coupled to a resistive switching device to provide rectification for the resistive switching device to form a non-volatile memory device.

Journal ArticleDOI
TL;DR: In this article, high quality Bi2Te3 and Sb2Te 3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy.
Abstract: High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111) substrate is better than a vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3 topological insulator films can be directly grown on a GaAs (111) substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate the modification of the electronic properties of single layer chemical vapor deposition (CVD)-grown graphene by deep ultraviolet (DUV) light irradiation and construct a p-n junction by DUV light exposure on selected regions of graphene, and investigated it with gate voltage dependent resistivity measurements and currentvoltage characteristics.
Abstract: We demonstrate the modification of the electronic properties of single layer chemical vapor deposition (CVD)-grown graphene by deep ultraviolet (DUV) light irradiation. The shift in the G and 2D bands in Raman spectra towards higher wavenumber suggests p-doping in graphene field effect transistors (FETs). In the transport measurements, the Dirac point is shifted towards positive gate voltage with increasing DUV light exposure time, revealing the strong p-doping effect without a large resistance increase. The doping is found to be stable in graphene devices, with a slight change in mobilities. We also constructed a p–n junction by DUV light exposure on selected regions of graphene, and investigated it with gate voltage dependent resistivity measurements and current–voltage characteristics.

Journal ArticleDOI
TL;DR: In this paper, thermal diffusion of Ag acceptor into melt-grown Mg 2 Si single-crystalline substrates (electron concentration = 2×10 15 ǫ cm −3 ) was used to investigate the infrared photoresponse of the material.

Journal ArticleDOI
TL;DR: In this paper, the X-ray photoelectron spectroscopic binding energy shifts, while subjecting samples to a variety of optical and electrical stimuli, information about charge accumulation on materials or surface structures can be obtained.

Journal ArticleDOI
TL;DR: A phase shifter with the lowest figure of merit is demonstrated by reducing the junction width to 200 nm along the phase-shifter and optimizing the doping levels of the PN junction for operation in nearly fully depleted mode.
Abstract: In this paper we study the optimization of interleaved Mach-Zehnder silicon carrier depletion electro-optic modulator. Following the simulation results we demonstrate a phase shifter with the lowest figure of merit (modulation efficiency multiplied by the loss per unit length) 6.7V-dB. This result was achieved by reducing the junction width to 200 nm along the phase-shifter and optimizing the doping levels of the PN junction for operation in nearly fully depleted mode. The demonstrated low FOM is the result of both low VπL of ~0.78 Vcm (at reverse bias of 1V), and low free carrier loss (~6.6 dB/cm for zero bias). Our simulation results indicate that additional improvement in performance may be achieved by further reducing the junction width followed by increasing the doping levels.

Journal ArticleDOI
TL;DR: In this paper, the authors investigate different possibilities of achieving a strong effect of negative differential resistance in graphene tunnel diodes, the operation of which is controlled by the interband tunneling between both sides of the PN junction.
Abstract: By means of numerical simulation based on the Green's function formalism on a tight binding Hamiltonian, we investigate different possibilities of achieving a strong effect of negative differential resistance in graphene tunnel diodes, the operation of which is controlled by the interband tunneling between both sides of the PN junction. We emphasize on different approaches of bandgap nanoengineering, in the form of nanoribbons (GNRs) or nanomeshes (GNMs), which can improve the device behaviour. In particular, by inserting a small or even zero bandgap section in the transition region separating the doped sides of the junction, the peak current and the peak-to-valley ratio (PVR) are shown to be strongly enhanced and weakly sensitive to the length fluctuations of the transition region, which is an important point regarding applications. The study is extended to the tunneling FET which offers the additional possibility of modulating the interband tunneling and the PVR. The overall work suggests the high potential of GNM lattices for designing high performance devices for either analog or digital applications.

Journal ArticleDOI
TL;DR: In this article, a p-n junction of NiO thin film has been realized, successfully exhibiting good rectifying behavior with efficient UV photodiode characteristics, providing suitable solution for low-cost visible blind UV photodetector application.
Abstract: The development of a short-wavelength p-n junction device is essentially important for the realization of transparent electronics for next-generation optoelectronics. Nickel oxide (NiO) thin films with a tunable electrical conductivity of both p-type and n-type under the optimized growth conditions using RF sputtering technique with high optical transmission in the visible region have been fabricated. The room-temperature conductivities for n-type and p-type NiO thin films were about 5.91 × 101 and 1.9 ×10-2 S·cm-1, respectively. A p-n junction of NiO thin film has been realized, successfully exhibiting good rectifying behavior with efficient UV photodiode characteristics, providing suitable solution for low-cost visible blind UV photodetector application.


Journal ArticleDOI
TL;DR: In this article, the physical properties of InGaN p-n junction solar cells, such as the short circuit current density (JSC), open circuit voltage (Voc), fill factor (FF), and conversion efficiency (η), are theoretically calculated and simulated by varying the device structures, position of the depletion region, indium content, and photon penetration depth.
Abstract: InGaN p-n junction solar cells with various indium composition and thickness of upper p-InGaN and lower n-InGaN junctions are investigated theoretically. The physical properties of InGaN p-n junction solar cells, such as the short circuit current density (JSC), open circuit voltage (Voc), fill factor (FF), and conversion efficiency (η), are theoretically calculated and simulated by varying the device structures, position of the depletion region, indium content, and photon penetration depth. The results indicate that an In0.6Ga0.4N solar cell, with optimal device parameters, can have a JSC ~31.8 mA/cm2, Voc ~0.874 volt, FF ~0.775, and η ~21.5%. It clearly demonstrates that medium-indium-content InGaN materials have the potential to realize high efficiency solar cells. Furthermore, the simulation results, with various thicknesses of the p-InGaN junction but a fixed thickness of the n-InGaN junction, shows that the performance of InGaN solar cells is determined by the upper p-InGaN junction rather than the n-InGaN substrate. This is attributed to the different amount of light absorption in the depletion region and the variation of the collection efficiency of minority carriers.

Journal ArticleDOI
TL;DR: In this article, an n + p homo-junction structure was constructed for indium gallium nitride (InGaN) using In 0.16 Ga 0.84 N films.

Patent
27 Nov 2013
TL;DR: In this paper, a control structure is arranged to form an inversion layer in the drift and barrier regions in an invert state, and a noninversion layer is formed in the non-inversion state.
Abstract: In a semiconductor device a barrier region is sandwiched between a drift region and a charge carrier transfer region. The barrier and charge carrier transfer regions form a pn junction. The barrier and drift regions form a homojunction. A mean impurity concentration in the barrier region is at least ten times as high as an impurity concentration in the drift region. A control structure is arranged to form an inversion layer in the drift and barrier regions in an inversion state. No inversion layer is formed in the drift and barrier regions in a non-inversion state.

Journal ArticleDOI
TL;DR: In this article, a radial pn junction nanowire (NW) with surface depletion was solved for a radial energy band and electric field profiles, and an optimum device design was proposed to satisfy material, optical and electrostatic constraints in high efficiency NW solar cells.
Abstract: Poisson's equation is solved for a radial pn junction nanowire (NW) with surface depletion. This resulted in a model capable of giving radial energy band and electric field profiles for any arbitrary core/shell doping density, core/shell dimensions, and surface state density. Specific cases were analyzed to extract pertinent underlying physics, while the relationship between NW specifications and the depletion of the NW were examined to optimize the built-in potential across the junction. Additionally, the model results were compared with experimental results in literature to good agreement. Finally, an optimum device design is proposed to satisfy material, optical, and electrostatic constraints in high efficiency NW solar cells.

Journal ArticleDOI
TL;DR: In this article, an analytical model for the depletion capacitance of silicon-on-insulator (SOI) optical modulation diodes was derived and the model accurately describes the parasitic fringe capacitances due to a lateral pn junction and can be extended to other geometries, such as vertical and interdigitated junctions.
Abstract: We derive an analytical model for the depletion capacitance of silicon-on-insulator (SOI) optical modulation diodes. This model accurately describes the parasitic fringe capacitances due to a lateral pn junction and can be extended to other geometries, such as vertical and interdigitated junctions. The model is used to identify the waveguide slab to rib height ratio as a key geometric scaling parameter for the modulation efficiency and bandwidth for lateral diodes. The fringe capacitance is a parasitic effect that leads to a decrease of about 20% in the modulation bandwidth of typical SOI diodes without a corresponding increase in the modulation efficiency. From the scaling relations, the most effective way to increase the modulation bandwidth is to reduce the series resistance of the diode.

Journal ArticleDOI
TL;DR: The quantum efficiency spectra show that radial transport based on the shallow phosphorus doping of SiNW array improves the carrier collection property and then enhances the blue wavelength region response.
Abstract: A radial p-n junction solar cell based on vertically free-standing silicon nanowire (SiNW) array is realized using a novel low-temperature and shallow phosphorus doping technique. The SiNW arrays with excellent light trapping property were fabricated by metal-assisted chemical etching technique. The shallow phosphorus doping process was carried out in a hot wire chemical vapor disposition chamber with a low substrate temperature of 250°C and H2-diluted PH3 as the doping gas. Auger electron spectroscopy and Hall effect measurements prove the formation of a shallow p-n junction with P atom surface concentration of above 1020 cm−3 and a junction depth of less than 10 nm. A short circuit current density of 37.13 mA/cm2 is achieved for the radial p-n junction SiNW solar cell, which is enhanced by 7.75% compared with the axial p-n junction SiNW solar cell. The quantum efficiency spectra show that radial transport based on the shallow phosphorus doping of SiNW array improves the carrier collection property and then enhances the blue wavelength region response. The novel shallow doping technique provides great potential in the fabrication of high-efficiency SiNW solar cells.

Journal ArticleDOI
TL;DR: The double-gate light-emitting electrochemical transistor (DG-LECT) provides a new tool to study the fundamental physics of LECs, as it dissects the key working process of L EC into decoupled p-doping, n-doped, and electroluminescence.
Abstract: In conventional light-emitting electrochemical cells (LECs), an off-centered p-n junction is one of the major drawbacks, as it leads to exciton quenching at one of the charge-injecting electrodes and results in performance instability. To combat this problem, we have developed a new device configuration, the double-gate light-emitting electrochemical transistor (DG-LECT), in which the location of the light-emitting p-n junction can be precisely defined via the position of the two gate terminals. Based on a planar LEC structure, two gate electrodes made from an electrochemically active conducting polymer are employed to predefine the p- and n-doped area of the light-emitting polymer. Thus, a p-n junction is formed in between the p-doped and n-doped regions. We demonstrate a homogeneous and centered p-n junction as well as other predefined junction patterns in these DG-LECT devices. Additionally, we report an electrical model that explains the operation of the DG-LECTs. The DG-LECT device provides a new tool to study the fundamental physics of LECs, as it dissects the key working process of LEC into decoupled p-doping, n-doping, and electroluminescence.

Journal ArticleDOI
TL;DR: By employing lithium and nitrogen codoping method, p-type zinc oxide (ZnO) films have been prepared, and the ptype conduction can maintain for 207 days.
Abstract: By employing lithium and nitrogen codoping method, p-type zinc oxide (ZnO) films have been prepared, and the p-type conduction can maintain for 207 days. ZnO p-n junctions have been constructed based on the p-type ZnO. Under the drive of continuous current, obvious emission has been observed from the p-n junctions, and the ZnO p-n junction light-emitting devices (LEDs) can still work after placing in air ambient for 180 days. Room temperature electroluminescence spectra of the p-ZnO:(Li, N)/n-ZnO structured LEDs under continuous current recorded intermittently for 180 days. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim