Light soaking effect on defect states distribution of Hydrogenated amorphous silicon investigated By means of constant photocurrent technique
| Autor: | T. Tibermacine, A. Merazga |
|---|---|
| Jazyk: | English<br />French |
| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | Revue des Énergies Renouvelables, Vol 13, Iss 1, Pp 63 – 70-63 – 70 (2010) |
| Druh dokumentu: | article |
| ISSN: | 1112-2242 2716-8247 |
| Popis: | In the present paper we have investigated, by using the constant photocurrent method in dc-mode (dc-CPM), the effect of the light soaking (LS) on the deep defect density (Nd) and the slope of the Urbach tail (E0) of a slightly phosphorus-doped hydrogenated amorphous silicon (a-Si:H) film prepared by Plasma-Enhanced Chemical Vapour Deposition (PECVD). By applying the derivative method, we have converted the measured data into a density of states (DOS) distribution in the lower part of the energy gap. The evolution of the sub-band-gap absorption coefficient and the CPMdetermined density of gap-states distribution within the gap versus the illumination time leads to: (i) an increase in the deep defect absorption without any significant changes in the Urbach tail (exponential part), (ii) a presence of more charged than neutral defects as predicted by the defect pool model, and (iii) a saturation point of the degradation of both optical absorption coefficient and density of deep states of slightly P-doped sample measured by dc-CPM. The constant photocurrent technique in dc-mode as a spectroscopy method for the defect distribution determination is, therefore, most reliable to study the light soaking effect on the stability of hydrogenated amorphous silicon layers used in solar cells manufacturing. |
| Databáze: | Directory of Open Access Journals |
| Externí odkaz: |
|