Photoresponse Modeling and Analysis of InGaP/GaAs Double-HPTs

Photoresponse of GaAs-based double-heterojunction phototransistors (DHPTs), in surface-illuminated orientation, has been analyzed with a modified small-signal model. The effect of incident optical illumination on various intrinsic parameters has been discussed for In0.49Ga0.51P/GaAs N+p+N− DHPT. Since the primary detecting material is GaAs, the device is optimized to detect short wavelength at 850 nm. A novel formulation for optical flux absorption in DHPTs is also provided along with its comparison with single-heterojunction phototransistors. The analysis of DHPTs presented in this paper can be utilized for performance enhancement through device optimization in sensors, photoreceivers in optical networks, and remote sensing applications employing integrated circuits.