Performance analysis of infrared heterojunction phototransistors based on Type-II superlattices.

• High performance T2SLs-based heterojunction phototransistors were demonstrated. • The HPT exhibits an optical gain of 345.3 at 1.6 μm at room temperature. • A −3 dB cut-off frequency of 5.1 GHz was achieved at 150 K for the HPT. In this study, a comprehensive analysis of the n-p-n infrared heterojunction phototransistors (HPTs) based on Type-II superlattices has been demonstrated. Different kinds of Type-II superlattices were carefully chosen for the emitter, base, and collector to improve the optical performance. The effects of different device parameters include emitter doping concentration, base doping concentration, base thickness and energy bandgap difference between emitter and base on the optical gain of the HPTs have been investigated. By scaling the base thickness to 20 nm, the HPT exhibits an optical gain of 345.3 at 1.6 μm at room temperature. For a 10 μm diameter HPT device, a −3 dB cut-off frequency of 5.1 GHz was achieved under 20 V at 150 K. [ABSTRACT FROM AUTHOR]