Graded Al Component AlGaN Heterojunction Nanowire Array Photocathode

The Al_xGa_1−xN material with tunable response cutoff wavelength has gained widespread attention in optoelectronic detection. A photoemission model for Al_xGa_1−xN heterojunction nanowire array with a gradient Al composition is constructed. The built-in electric field of heterojunction and the photocathode response bands are regulated by adjusting the height of Al_xGa_1−xN sublayer and Al component in the nanowire. The effects of nanowire geometry and incident angle on the quantum efficiency of Al_xGa_1−xN nanowire arrays with gradient Al components are analyzed. The geometry-optimized Al_0.6Ga_0.4N-Al_0.75Ga_0.25N nanowires with an incident angle of 10° exhibit a maximum quantum efficiency of 58.27%, which increased by 95.01% compared to that under the incident angle of 0°.