Effects of light induced degradation on the distribution of deep defects in hydrogenated amorphous silicon-germanium alloys
Book
·
OSTI ID:527690
- Univ. of Oregon, Eugene, OR (United States)
- Lawrence Berkeley Lab., CA (United States). Physics Div.
Although a-Si,Ge:H alloys have been increasingly studied in recent years because of their desired tunable band gaps for application in tandem solar cells, the relation between the mid gap defects with solar cell performance is still not completely clear. The authors have characterized the defect state structure in a series of device quality glow discharge produced a-Si,Ge:H alloys with Ge content ranging from 30 at.% to 50 at.% using capacitance profiling, modulated photocurrent, transient junction photocurrent and photocapacitance measurements. As previously reported, these methods allows one to identify two types of thermally induced defect transitions plus two types of optical transitions from deep defects. In the current study the authors have examined the changes in these defects, along with the changes in the hole mobility-time products, that result from prolonged light exposure. By comparing these changes in the annealed state and light soaked state of the same sample, they attempt to correlate the changes in defects with the hole mobility-time product. In general, although all of the defect bands are found to increase after light soaking, the relative factor is found to be different for the various defect transitions within the same sample. The authors also try to identify a defect bands may be acting as a safe electron trap, enhancing the lifetime of the minority carriers. They propose that the observed decrease of this defect band relative to the midgap defect band with light soaking could be a significant factor in determining the degradation of these a-Si,Ge:H alloys in the device performance.
- OSTI ID:
- 527690
- Report Number(s):
- CONF-960401--; ISBN 1-55899-323-1
- Country of Publication:
- United States
- Language:
- English
Similar Records
The significance of charged defects in understanding the light-induced degradation of hydrogenated amorphous silicon-germanium alloys
Microscopic Origins of Metastable Effects in a-Si:H and Deep Defect Characterization in a-Si,Ge:H Alloys, Annual Subcontract Report, 1 February 1992 - 31 January 1993
Identifying Electronic Properties Relevant to Improving Stability in a-Si:H-Based Cells and Overall Performance in a-Si,Ge:H-Based Cells; final Subcontract Report, 18 April 1994-15 January 1998
Conference
·
Tue Jul 01 00:00:00 EDT 1997
·
OSTI ID:20085460
Microscopic Origins of Metastable Effects in a-Si:H and Deep Defect Characterization in a-Si,Ge:H Alloys, Annual Subcontract Report, 1 February 1992 - 31 January 1993
Technical Report
·
Sat Jul 31 20:00:00 EDT 1993
·
OSTI ID:10180625
Identifying Electronic Properties Relevant to Improving Stability in a-Si:H-Based Cells and Overall Performance in a-Si,Ge:H-Based Cells; final Subcontract Report, 18 April 1994-15 January 1998
Technical Report
·
Sun Nov 15 19:00:00 EST 1998
·
OSTI ID:6699