Technological advances in a-Si: H/c-Si Heterojunction solar cells

Year 2014, Volume: 4 Issue: 2, 528 - 538, 01.06.2014

Kamlesh Patel Pawan K Tyagi

Abstract

Cost effective silicon-based thin-film solar cells have attained a sustainable age with stable in comparison to the crystalline silicon solar cells. The heterojunction solar cells based on amorphous silicon/crystalline silicon heterostructures are producing efficiency more than 22%. The research activities have led to such high efficiency through a number of technological developments. To make the surface passivation better at the top of c-Si substrate, a thin intrinsic a-Si: H layer is deposited in between the a-Si:H layer and c-Si substrate and such configuration has famous as Heterojunction with Intrinsic Thin-layer (HIT) solar cells. Various research methodologies used for the efficiency improvement in HIT cells have been developed in ages and now the HIT cells with efficiency better than 24% are being manufactured. The simultaneous developments of characterization methods well supported the improvements in fabrication technologies to analyze their self-governing effects on the deposited amorphous films, c-Si substrates and device performances. A number of characterization facilities have been established, which are based on the evaluation of effective carrier lifetime, density of interface states, recombination rate, cell efficiency, band offset, current density-voltage characteristics, charge carrier concentration, photoluminescence, activation energy etc.  The present paper reviews the fabrication technologies for the development of these reported solar cells and their characterizations as well at the material and device levels.

Keywords

Cell efficiency; heterojunction; HIT cell; PECVD; Thin film silicon

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