Low shot noise GaAs/AlGaAs heterojunction phototransistors grown by MBE with aδ-doped base

摘要

Novel GaAs/AlGaAs heterojunction phototransistors with a δ-doped base have been fabricated. Very high gain and low output noise have been measured. The measured noise is composed of shot noise associated with collector quiescent bias current and amplified shot noise due to collector leak current for non-passivated devices. For well-passivatcd devices, the measured noise is, as predicted previously [Y. Wang, E.S. Yang, J. Appl. Phys. 74 (1993) 6978], just composed of the shot noise associated with collector quiescent bias current. The high gain and low intrinsic noise characteristics of these transistors make them very promising in weak light detection.