[OPTICAL REVIEW Vol. 2, No. 2 (1995) 120-122]
2-D Simulation and New Structures of Heterojunction Phototransistor for Higher Optical Amplification in Optoelectronic Integrated Devices
Vahid AHMADI,1 Susumu NODA2 and Akio SASAKI2
1Present address : Dept. of Electr. Eng., Tarbiat Modarres University, P.O. Box 14155-4838, Tehran, Iran, 2Department of Electrical Engineering, Kyoto University, Kyoto, 606-01 Japan
(Accepted November 25, 1994)
The improvement of optical gain is an important priority for performance design in most of optoelectronic integrated devices (OEIDs). A two-dimensional simulator is developed for the rigorous analysis and optimum design of devices. With it, we analyze the characteristics of heterojunction phototransistor (HPT) which acts as a light-detector in OEID, and we propose new structures of HPT to increase the conversion gain without much increase in dark current. Then, the simulation of an OEID composed of an HPT integrated over a light-emitting diode (LED) is implemented, and it is shown that the new structures significantly improve the optical amplification for low input light power over the conventional structure.
Key words : heterojunction phototransistor, two-dimensional simulation, optoelectronic integrated device