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Research Article Open Access

Investigation of structural aspect in terms of atypical phases within material deposited for a-Si:H solar cell fabrication 

Mansi Sharma1,2, Deepika Chaudhary1,2, S. Sudhakar1, Preetam Singh1, K.M.K. Srivatsa1,2, Sushil Kumar1,2 *

1Network of Institutes for Solar Energy (CSIR-NISE), Physics of Energy Harvesting Division, CSIR – National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 India

2Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL Campus, Dr. K.S. Krishnan Marg,
 New Delhi 110012 India

Adv. Mater. Proc., 2016, 1 (1), 6

DOI: 10.5185/amp.2016/107

Publication Date (Web):05 September 2016

Copyright © IAAM-VBRI Press

Abstract


Abstract

The structural investigation of the a-Si:H material, deposited at different pressures by PECVD process, has been carried out to analyze the signatures of diffused intermediate sort of crystalline phases within the amorphous silicon matrix.  Raman characterization along with the Photoluminescence (PL) and spectroscopic ellipsometry studies were carried out to understand the microstructuree of these films. From Raman analysis the material was found to have indistinguishable crystalline phase, which can also be named as “intermediate amorphous phase” (a phase defined between amorphous and ultra nano-crystalline silicon) with crystalline volume fractions as 56 % and 62 % for 0.23 Torr and 0.53 Torr respectively. Here the contribution of ultra nano-crystallites results in higher crystalline fraction, which is not visibly revealed from the Raman spectra due to its sub nano-crystallite characteristics. For the film deposited at 0.53 Torr  stable photo-conductance in conjunction with high photo-response under 10 hour light soaking has been observed, which is as expected due to high crystalline volume fraction. The presence of these phases might be the possible reason for the distinct device characteristics though having nearly the similar electrical properties (photo-response ~104).  These studies will help to make improvement in the individual layer properties, other than the interface effect, in the fabrication of efficient p-i-n solar cells. Copyright © 2016 VBRI Press

Keywords


PECVD, a-Si:H, ellipsometer, raman spectra, PL spectra.