Research on quantum efficiency of GaN wire photocathode

2020

Int J Energy Res

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Summary The field‐assisted method is proposed to increase electron capture of the GaN nanowire cathode. We deduce the photoemission or electron collection efficiencies of the field‐assisted uniform‐doping and exponential‐doping cathodes using the diffusion‐drift formula. Results show that the external electric field has a significantly better collection efficiency for uniform‐doping nanowire cathodes than that of exponential‐doping. In cathodes without a build‐in field, quantum efficiency and collection efficiency reached a maximum at incident angles of 65° and 45°, and field intensity of 0.1 and 0.7 V/μm, respectively. The external electric field also contributes to the polarization of GaN nanowires. The field‐assisted GaN NWAs (nanowirearray) cathode could improve the photoemission performance and are expected to be realized in the follow‐up experiment.

Section: Model and Derivationmentioning

confidence: 99%

Section: Model and Derivationmentioning

confidence: 99%

Section: Model and Derivationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of quantum and collection efficiency of field‐assisted uniform‐doping and exponential‐doping GaN nanowire cathodes

2020

Int J Energy Res

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Enhancement of Electron Collection and Light Trapping of Inclined GaN and AlGaN Nanowire Arrays

Zhangyang

2021

Energy Tech

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The structural design of excellent absorption and electron collection is the main challenge of the nanowire array (NWA) photocathode. Herein, the light trapping and photoemission performance of GaN and graded compositional AlGaN‐inclined NWA are systematically researched. The finite‐difference time domain method (FDTD) is used to calculate the light absorption under different inclined angles and array spacings. The results show that the NWA with an inclined angle of 0.4°–0.6° has greater light‐trapping capacity, which obtains up to 97% light absorption at a wavelength of 267 nm. The inclined graded compositional AlGaN NWA with a built‐in electric field has better photoemission performance. The external electric field further improves the electron collection capacity of the NWA cathode. The inclined AlGaN NWA cathode with the best parameters θ = 0.6°, L = 180 nm, and Eout = 2 V μm−1 obtains a quantum efficiency of 47.57% and collection efficiency of 31.09%. The study of the inclined graded compositional AlGaN NWA cathode assisted by the electric field provides an effective method for further utilization of incident light and emitted electrons.

Theoretical study on the optoelectronic properties of GaAs nanostructures with Al component gradient change

Sun

et al. 2020

Int J Energy Res

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In order to improve the photoemission characteristics of the GaAs photocathode, GaAs nanostructures (nanoholes and nanowires) with three sublayers and Al component of gradient distribution are designed in this article. Finite element method was used to study the effects of Al component gradient interval, component range, height, diameter, and other parameters on light absorption of nanostructures. And the quantum efficiency of these nanostructures was calculated. The results show that the wide band absorption can be achieved with small gradient interval and component variation range, and the nanostructure can enhance the light capture ability with certain angle inclination. In the gradient component nanostructures, the thickness of the top most layer has a great influence on the quantum efficiency. Highlights • The nanohole and nanowire structures with three sublayers and Al component gradient distribution were designed. • The effects of gradient interval, range of Al components, and geometric parameters on the optical properties of nanostructures are discussed.