Si1?XGeX/Si quantum well infrared photodetectors

Abstract

P-type Si1−XGeX/Si quantum well infrared photodetectors for thermal imaging applications have been grown by low pressure vapour phase epitaxy for the first time. Good control of periodicity in these pseudomorphic multiple quantum well structures on Si substrates was demonstrated by real-time ellipsometry during growth and subsequently confirmed by transmission electron microscopy. The photoresponse spectrum was tuned in the 8–13 Μm waveband by varying the Ge fraction in the Si1−XGeX quantum wells. Dark currents were reduced by doping only the centre regions of the quantum wells.