Theoretical research on optical properties and quantum efficiency of Ga(1_x)Al_xN photocathodes

摘要

In order to design the optimal component structure of transmission-mode (t-mode) Ga_(1_x)Al_xN photocath- ode, the optical properties and quantum efficiency of Gai_xAlxN photocathodes are simulated. Based on thin film principle, optical model of t-mode Ga_(1_x)A1_xN photocathodes is built. And the quantum efficiency formula is put forward. Results show that Gai_xAl_xN photocathodes can satisfy the need of detectors with "solar blind" property when the Al component is bigger than 0.375. There is an optimal thickness of Gai_xAl_xN layer to get highest quantum efficiency, and the optimal thickness is 0.3 μm. There is close relation between absorptivity and quantum efficiency, which is in good agreement with the "three-step" model. This work gives a reference for the experimental research on the Gai_xAl_xN photocathodes.