A simple, analytical model is used to investigate the steady-state responsivity of GaN-based, p-i-n photodiodes. The trends exhibited by recent experimental data are reproduced and, in so doing, deficiencies in present GaN material, and inadequacies in electrical- and optical-parameter specification, are identified. The model is used to suggest that heterojunction diodes, fabricated from materials in the AlxGa1-xN ternary system, could produce practically important, specialized, UV photodetectors. (C) 1998 Elsevier Science Ltd. All rights reserved.
