Measurements are reported of the luminescence, time-of-flight photoconductivity and electron spin resonance (ESR) in a-Si: Ge: H alloys. In the alloys it is found that the luminescence intensity varies with defect density according to a tunnelling model similar to that in a-Si:H. However, the tunnelling distance decreases with Ge concentration up to about 30% and then increases. This nonmonotonic behaviour is attributed to the additional chemical disorder of the alloys. Time-of-flight experiments confirm that the dangling bonds are the dominant deep trap in the alloys. We find that the capture cross-sections for electrons and holes are very similar to those measured in a-Si: H, and are independent of whether the trap is a Ge or Si dangling bond.
|Original language||English (US)|
|Number of pages||15|
|Journal||Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties|
|State||Published - Sep 1987|
Bibliographical noteFunding Information:
We are grateful to R. Thompson and J. Zesch for technical assistance. The research is supported by the Solar Energy Research Institute.