ABSTRACTWe have studied the spectrum of various types of a-SiGe:H alloys for pin and Schottky barrier photodlodes, in which the band gaps of the a-SiGe:H vary between 1.75 eV and 1.35 eV. It has been found that the spectral re-ponse of the Schottky barrier diode shifts significantly to longer wavelength and the quantum efficiency decreases with an increase in i layer thickness. However, for the pin diode, an increase in the i layer thickness can hardly shift the spectrum to longer wavelength. For both pin and Schottky barrier diodes, the quantum efficiency can be increased by increasing the reverse bias. Therefore, an enhanced spectrum with a maximum at 800nm and a tail to lun can be achieved for a reverse-biased a-SiGe:H Schottky barrier diode. The results indicate that a-SiGe:H has a great potential for a low cost infrared photodetector.
Silicon pin diode array hybrids for charged particle detection