Title :
Capacitance - frequency analysis of CdTe photovoltaics
Author :
Shvydka, Diana ; Jayamaha, U. ; Karpov, V.G. ; Compaan, A.D.
Author_Institution :
First Solar LLC, Perrysburg, OH, USA
Abstract :
We present data on frequency dependent capacitance for fresh and degraded CdS/CdTe devices in a broad range of frequency from 0.1 to 105 Hz and for various temperatures. The data are consistent with the model where defects have continuous, energy dependent density of states (DOS) in the forbidden gap. The DOS is found to change in the course of device degradation. We introduce the concept of a single defect capacitance and pay special attention to interpreting the temperature dependence of our data. To ensure the interpretation where DOS is temperature independent we take into account the multiphonon character of the trapping-detrapping electron transitions.
Keywords :
II-VI semiconductors; cadmium compounds; capacitance; defect states; electron traps; phonons; semiconductor device measurement; solar cells; CdTe; CdTe photovoltaics; capacitance-frequency analysis; defect states; density of states; device degradation; multiphonon character; single defect capacitance; temperature effects; trapping-detrapping electron transitions; Capacitance measurement; Degradation; Extraterrestrial measurements; Frequency measurement; Photovoltaic cells; Physics; Semiconductor thin films; Temperature dependence; Temperature distribution; Temperature measurement;
Conference_Titel :
Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE
Print_ISBN :
0-7803-7471-1
DOI :
10.1109/PVSC.2002.1190674
