A novel homojunction interfacial workfunction internal photoemission (HIWIP) far-infrared (FIR) detector based on the interfacial workfunction (IWF) between a heavily doped absorber/emitter layer and a lightly doped (or intrinsic) layer is reported. The detector structures are classified according to their emitter layer doping concentrations (N_d). The threshold wavelength ((lambda) _t) is tunable in the IR wavelength range by changing N_d and bias voltage. This detector concept has been successfully demonstrated using forward biased commercial Si and Ge p-i-n diodes at 4.2 K. Threshold wavelengths ((lambda) _t) from around 40 - 220 micrometers for Si and up to 240 micrometers for Ge were experimentally obtained. A theoretical investigation including an estimation of workfunction dependence on N_d, quantum efficiency calculations, and dark current analysis is reported. Based on these results, the detector noise equivalent power (NEP) limited by thermal noise and background noise is calculated.

Date Published: 6 June 1995
PDF: 12 pages
Proc. SPIE 2475, Infrared Detectors and Instrumentation for Astronomy, (6 June 1995); doi: 10.1117/12.211244

Published in SPIE Proceedings Vol. 2475:
Infrared Detectors and Instrumentation for Astronomy
Albert M. Fowler, Editor(s)