Far Infrared Detectors using p-Si1-xGex/Si Multiple Quantum Wells

The first systematic study of p-Si
1-x
Ge
x
/Si multiple quantum well infrared detectors (QWIPs) grown by low pressure vapour phase epitaxy (LPVPE) is described. The inclusion of undoped Si
1-x
Ge
x
spacer layers adjacent to the p-doped alloy reduces the weakly temperature-dependent ``tunnelling'' component of the dark current. The peak wavelength in the photoresponse spectrum is tuned between 7.2-10.2μm by changing the Ge fraction, x, in the range between 0.15 alnd 0.08.