Extrinsic base surface-passivated dual-emitter heterojunction phototransistors

Low-Dark-Current Heterojunction Phototransistors with Long-Term Stable Passivation Induced by Neutralized (NH4)2S Treatment

“…Surface leakage particularly degrades the low-bias performance of heterojunction bipolar transistors (HBTs) [1][2][3][4][5][6][7][8][9][10][11] and the low-power optical performance of heterojunction phototransistors (HPTs). 12) These defects mainly result from native surface oxides, the nature of dangling bonds, and the disruption of the crystal lattice at the etched mesa edge. They are known to detrimentally affect the electrical and optical characteristics of GaAsbased electronic and optoelectronic devices.…”

“…17) For HPTs, there have been some reports on employing an emitter ledge structure to enhance the optical performance. 12,18,19) However, no reports have focused on HPT with sulfur passivation treatment. In this work, the temperature-dependent dark and optical characteristics of InGaP/GaAs HPTs were investigated.…”

Promoted Potential of Heterojunction Phototransistor for Low-Power Photodetection by Surface Sulfur Treatment

“…Accordingly, an emitter ledge structure has also been reported to enhance the optical performance of heterojunction phototransistors ͑HPTs͒. Bansropun et al, 16 Tan et al, 17 and Chen et al 18 have verified the capability of employing an emitter ledge structure to enhance the dc current gain as well as the optical gain of HPTs. For low-power photodetection, dark current is also an important index to examine the quality of a photodetector and must be quashed.…”