High detectivity InGaAs base infrared hot-electron transistor

Abstract

An infrared hot‐electron transistor with a thin (300 Å)InGaAs base layer is constructed. By adopting a thin base material with a large Γ‐L valley separation, the photocurrent transfer ratio is improved by a factor of four in comparison with the GaAs base transistor. As a result, the detectivity of the transistor is increased to 1.4×10¹⁰ cm√Hz/W at 77 K with a cutoff wavelength of 9.5 μm, two times as large as the companion state‐of‐the‐art GaAs quantum well photoconductor. Combined with the lower dark current, the voltage responsivity and the noise equivalent temperature difference of a detector array can be improved by more than an order of magnitude.