Demonstration of Si homojunction far-infrared detectors

Abstract

A 48 μm cutoff wavelength (λc) Si far-infrared (FIR) detector is demonstrated. Internal photoemission over a Si interfacial work-function of a homojunction consisting of molecular beam epitaxy grown multilayers (p+ emitter layers and intrinsic layers) is employed. The detector shows high responsivity over a wide wavelength range with a peak responsivity of 12.3±0.1 A/W at 27.5 μm and detectivity D* of 6.6×1010 cmHz/W. The λc and bias dependent quantum efficiency agree well with theory. Based on the experimental results and the model, Si FIR detectors (40–200 μm) with high performance and tailorable λcs can be realized using higher emitter layer doping concentrations.