Extended short wavelength infrared heterojunction phototransistors based on type Ⅱ superlattices

摘要

A two terminal extended short wavelength infrared heterojunction phototransistor based on type-II InAs/AlSb/GaSb on a GaSb substrate is designed, fabricated, and investigated. With the base thickness of 40nm, the device exhibited a 100% cut-off wavelength of approximate to 2.3m at 300K. The saturated peak responsivity value is 320.5A/W at 300K, under front-side illumination without any antireflection coating. A saturated optical gain of 245 at 300K was measured. At the same temperature, the device exhibited a collector dark current density (at unity optical gain) and a DC current gain of 7.8x10(-3) A/cm(2) and 1100, respectively. The device exhibited a saturated dark current shot noise limited specific detectivity of 4.9x10(11)cmHz(1/2)/W at 300K which remains constant over a broad range of wavelengths and applied biases.