GaAs double-heterostructure photodetectors

Abstract

Al_xGa_1−xAs‐GaAs structures grown by LPE have been investigated for optical power conversion at 8500 Å. Comparison is made between single‐ and double‐heterostructure configurations, both in theory and experiment; relative merits of each structure are discussed. Good I‐V characteristics have been realized for these devices, with series resistance as low as 0.16 Ω. For small‐area (5–6 mm²) devices operating at a few mW power, fill factors between 0.75 and 0.81 and internal quantum efficiencies exceeding 90% have been achieved for each structure investigated. Power conversion efficiencies as high as 46% were obtained at 8500 Å, after correcting for reflection losses; this approaches the theoretical limit for space‐charge‐limited devices. The devices were also evaluated as solar batteries, with efficiencies of 13–14% reported, corresponding to internal efficiencies as high as 18%.