Optical devices from AlGaAs-GaAs HBTs heavily doped with amphotericSi

A new optoelectronic multifunctional device, having triple function of light emission, detection and amplification have been developed and some preliminary integrated circuits are demonstrated. The devices consist of N-p-n or N-P-n AlGaAs-GaAs HBT utilizing amphoteric Si heavily-doped GaAs or AlGaAs p-type base layer. Maximum current gain of 3600, and light output power of about 0.17 μW with 100 μA base current (I_b) in transistor mode operation and of about 10 μW with I_b=40 mA in diode mode operation are obtained. The optical emission wavelengths in both are about 0.85-0.86 μm. Optical gain of about 130 was obtained near the 0.86 μm wavelength as a detection transistor. Spectrum matching between emission and detection wavelength range is achieved. Some monolithic integrated circuits constituted of the transistors are proposed and demonstrated successfully. The relationship between current gain and radiative quantum efficiency at the transistor operation is also discussed