Title :
Fabrication and characteristics of AlxGa1-xAs heterojunction phototransistors with wide-gap window
Author :
Zhu, Yu ; Komatsu, Yoshihiko ; Noda, Susumu ; Takeda, Yoshikazu ; Sasaki, Akio
Author_Institution :
Dept. of Electr. Eng., Kyoto Univ., Japan
fDate :
6/1/1991 12:00:00 AM
Abstract :
The fabrication process and device characteristics of Al0.7 Ga0.3As/Al0.2Ga0.8As heterojunction phototransistors are described. The interface between the emitter and base layers becomes rough with the increase in the Al content of the emitter layer, and it causes a decrease in the optical conversion gain of the heterojunction phototransistors. A spacer layer with the same Al content as that in the emitter layer is inserted between the emitter and base layers. Both the interface morphology and the optical conversion gain are improved. Enhanced by the avalanche multiplication in the base-collector junction, an optical conversion gain of 1500 is achieved in spite of the shorter diffusion length in the Al0.2Ga0.8As base layer. The device exhibits a photoresponse in the range of 520-780 nm, i.e., from green to red light
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; phototransistors; semiconductor junctions; 520 to 780 nm; Al0.7Ga0.3As-Al0.2Ga0.8 As; AlxGa1-xAs; avalanche multiplication; base-collector junction; device characteristics; diffusion length; emitter layer; fabrication process; green to red light; heterojunction phototransistors; interface morphology; optical conversion gain; photoresponse; semiconductors; spacer layer; wide gap emitter; wide-gap window; Artificial intelligence; Gallium arsenide; Heterojunctions; Image intensifiers; Morphology; Optical device fabrication; Optical noise; Phototransistors; Stimulated emission; Substrates;
Journal_Title :
Electron Devices, IEEE Transactions on
