Band tails in hydrogenated amorphous silicon and silicon-germanium alloys
Abstract
The temperature dependence of the conduction- and valence-band tails has been determined by total-photoelectron-yield spectroscopy for doped and undoped a-Si:H and a-SiGe:H alloys. We find that all films possess purely exponential conduction- and valence-band-tail densities of states; however, the characteristic energy of the conduction-band tail increases much more rapidly with temperature than that of the valence-band tail. This indicates that the conduction-band tail is considerably more susceptible to thermal disorder than to structural disorder, whereas the reverse holds for the valence-band tail.
- Publication:
-
Physical Review Letters
- Pub Date:
- June 1990
- DOI:
- 10.1103/PhysRevLett.64.2811
- Bibcode:
- 1990PhRvL..64.2811A
- Keywords:
-
- 71.25.Mg;
- 71.55.Ht;
- Other nonmetals