Silicon holds the largest market share in solar photovoltaics, where Si wafer-based PV technology accounted for more than 95% of the total produ ction in 2022, according to the report by Fraunhofer ISE. The development of cost-effective and high efficiency Si solar cells is a flourishing sphere of research. The major shortcoming in the commercialized Si solar cells is the usage of the doped layers leading to parasitic absorption losses and the high thermal budget involved in fabricating the constituent layers. To mitigate these issues, carrier selective contact (CSC) Si solar cells proffer to be a solution.
The growth of ultrathin layers (?15nm) for this application with control over the thickness and conformality of the films grown on planar and textured surfaces becomes vital. These advantages are provided by the growth technique of atomic layer deposition (ALD) along with the use of lower deposition temperature. It also has been known to provide highly uniform films grown over large area substrates. With all the benefits of ALD, this study will comprise the fabrication of a complete device (CSC solar cell) on a large area wafer. The constituent layers of a typical CSC solar cell, namely (a) the passivation layer, (b) the carrier selective charge transport layers, and (c) the transparent conductive oxide, are being developed by plasma enhanced (PE) and thermal ALD. In this talk, I will present a literature overview of Si solar cells with particular emphasis on carrier selective contact solar cells. An overview of the growth technique used, i.e., ALD and the development of fi lms for photovoltaic applications will be discussed. The ultimate motive is to fabricate complete solar cell with (PE) ALD without vacuum break.
PhD Scholar, Department of Physics, IIT Madras