High-speed Al sub(0.2)Ga sub(0.8)As/GaAs multiquantum-well phototransistors with tunable spectral response

• Published in: IEEE electron device letters Vol. 14; no. 7; pp. 335 - 337
• Main Authors: Li, W Q, Karakucuk, M, Freeman, P N, East, J R, Haddad, G I, Bhattacharya, Pallab K
• Format: Journal Article
• Language: English
• Published: 01.01.1993
• ISSN: 0741-3106

We have measured the high-frequency characteristics and temporal response of a GaAs/AlGas heterojunction phototransistor with a GaAs/ Al sub(0.2)Ga sub(0.8)As multi-quantum-well collector. The quantum wells offer tunability of the photoresponse (10 nm for a bias change of 4 V) and a negative differential resistance in the photocurrent-voltage characteristics. Measured values of f sub(T) and f sub(max) are 20 and 6 GHz, respectively. The temporal response to short-pulse optical excitation is characterized by a linewidth of 46 ps. Such devices are attractive candidates for making optically induced oscillators.