Title :
The density of states distribution of a-Si1-xGex :H alloys
Author :
Pereira, Jorge Manuel Torres
Author_Institution :
Inst. Superior Tecnico, Tech. Univ. of Lisbon, Portugal
Abstract :
A model for the density of states (DOS) in the gap of a-SiGe:H alloys is presented. The effects of Ge content and structure are considered. An increase of the DOS around midgap due to Ge and Si dangling bonds is observed. The conduction (CB) and valence band (VB) tails are exponential. The slope of the CB tail increases when the Ge content increases and the deposition temperature decreases, whereas the slope of the VB tail remains unaffected. The narrowing of the optical gap on alloying may be viewed as the combined shift, in the opposite direction, of the CB edge and the VB edge
Keywords :
Ge-Si alloys; amorphous semiconductors; dangling bonds; electronic density of states; energy gap; hydrogen; amorphous Si1-xGex:H alloys; conduction band tail; dangling bonds; density of states distribution; deposition temperature; optical gap; semiconductor; valence band tail; Alloying; Amorphous silicon; Atom optics; Germanium alloys; Interface states; Iron; Optical devices; Silicon alloys; Tail; Temperature;
Conference_Titel :
Electrotechnical Conference, 1991. Proceedings., 6th Mediterranean
Conference_Location :
LJubljana
Print_ISBN :
0-87942-655-1
DOI :
10.1109/MELCON.1991.161757
