We show that the open circuit voltage (Voc) in hydrogenated amorphous silicon (a-Si:H) solar cells can be described by an analytical energy-barrier-dependent equation, considering thermionic emission as the physical mechanism determining the recombination current. For this purpose, the current-voltage characteristics of two device structures, i.e., a-Si:H(n)/a-Si:H(i)/a-Si:H(p)/AZO p-i-n solar cells with different p-doping concentrations and a-Si:H(n)/a-Si:H(i)/AZO Schottky structures with different intrinsic layer thicknesses, were analyzed in dark and under illumination, respectively. The calculated barrier in the p-i-n devices is consistent with the difference between the work function of the p-layer and the conduction band edge of the i-layer at the interface in thermal equilibrium.
Analytical energy-barrier-dependent Voc model for amorphous silicon solar cells
A. Castro-Carranza, J. C. Nolasco, N. Reininghaus, S. Geißendörfer, M. Vehse, J. Parisi, J. Gutowski, T. Voss; Analytical energy-barrier-dependent Voc model for amorphous silicon solar cells. Appl. Phys. Lett. 25 July 2016; 109 (4): 043503. https://doi.org/10.1063/1.4959939
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