Title :
Nature and densities of gap states in a-Si:H and a-SiC:H obtained from the quantitative analysis of photoconductivity
Author :
Gunes, M. ; Dawson, R.M. ; Lee, S. ; Wronski, C.R. ; Maley, N. ; Li, Y.M.
Author_Institution :
ECE Dept., Pennsylvania State Univ., University Park, PA, USA
Abstract :
The nature, distribution, and densities of midgap states in solar-cell-grade intrinsic hydrogenated amorphous silicon (a-Si:H) and hydrogenated silicon carbide (a-SiC:H) have been investigated using sub-bandgap photoconductivity and steady-state photoconductivity measurements. The sub-bandgap optical absorption was obtained by both constant photocurrent-method (CPM) and dual beam photoconductivity (DBP) techniques, and the experimental results were analyzed using detailed numerical modeling based on the Rose-Simmons-Taylor theory. The densities, energy distribution, and carrier capture cross-sections of midgap states were obtained from iterative procedure for the best fits of both sub-bandgap absorption and photoconductivities for the a-Si:H and a-SiC:H materials
Keywords :
amorphous semiconductors; electron energy states of amorphous solids; elemental semiconductors; hydrogen; impurity and defect absorption spectra of inorganic solids; photoconductivity; silicon; silicon compounds; solar cells; Rose-Simmons-Taylor theory; carrier capture cross-sections; constant photocurrent-method; dual beam photoconductivity; energy distribution; midgap states; numerical modeling; semiconductor; sub-bandgap optical absorption; sub-bandgap photoconductivity; Absorption; Amorphous silicon; Atmospheric measurements; Density measurement; Optical films; Optical filters; Photoconducting materials; Photoconductivity; Photonic band gap; Photovoltaic cells;
Conference_Titel :
Photovoltaic Specialists Conference, 1991., Conference Record of the Twenty Second IEEE
Conference_Location :
Las Vegas, NV
Print_ISBN :
0-87942-636-5
DOI :
10.1109/PVSC.1991.169473
