InP-Based Extended-Short Wave Infrared Heterojunction Phototransistor

• Published in: Journal of lightwave technology 2021-07, Vol.39 (14), p.4814-4819
• Main Authors: Xie, Zongheng, Deng, Zhuo, Huang, Jian, Xie, Zhiyang, Zhou, Zhiqi, Chen, Baile
• Format: Article
• Language: English
• Subjects: Bandwidth; Dark current; e-SWIR phototransistor; Electric fields; Frequency response; Heterojunctions; High gain; III-V semiconductor materials; Indium phosphide; Indium phosphides; InGaAs/GaAsSb T2SLs; Junctions; Lattice matching; Phototransistors; Room temperature; Short wave radiation; Shot noise; Substrates; Superlattices
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2021.3076238

In this paper, we report an InP-based extended-short wave infrared (e-SWIR) phototransistor with InGaAs/GaAsSb type-II superlattices (T2SLs) as the absorber. Monolithic growth of the phototransistor on InP substrate enjoys several benefits such as the lattice matching property and convenient bandgap engineering of the InP/InGaAs/GaAsSb material system. At room temperature, the device exhibits a dark current density of 4.57 A/cm 2 under −0.8 V bias, and the responsivity at 2 μm saturates at around 86 A/W. The corresponding thermal and shot noise limited specific detectivity is 6.59 × 10 10  cm·Hz 1/2 /W. The frequency response of the device is also measured by illuminating the device with a 2 μm modulated laser. The device shows a 10% to 90% rise time of 44.2 ns. These characterization results suggest the high gain phototransistor with InGaAs/GaAsSb T2SLs on InP substrate is a promising candidate for e-SWIR applications.