2017/12/18 by Sachenko, A. V., A. V. Bobyl, Bobyl, A. V. +16
Engineering · Materials Science · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Silicon Nanostructures and Photoluminescence #Silicon and Solar Cell Technologies #Thin-Film Transistor Technologies
paper · pdf · doi:10.48550/arxiv.1712.06653
openalex publication_date 2017/12/18 · openalex created_date 2018/01/05 · openalex updated_date 2026/07/28
Surface recombination affects both light-to-electricity and electricity-to-light conversion in solar cells (SCs). Therefore, quantitative analysis and reduction of surface recombination is an important direction in SC research. In this work, electroluminescence (EL) intensity and photoconversion efficiency of a set of 93 large-area (239 cm2) a-Si:H/c-Si heterojunction SCs (HJSCs) are measured under AM1.5 conditions at 298 K. The HJSC samples differed only in surface recombination velocity, S, but otherwise were identical. Variation in S was due to the variation of the chemical conditions under which the samples were treated. It is established that EL quantum efficiency, is affected by S much more strongly than photoconversion efficiency, η: namely, the reduction of the latter from 20.5% to 18% due to an increase of S is accompanied by a decrease of the former by more than an order of magnitude. In HJSCs with well passivated surfaces, i.e. low S, EL efficiency reached 2.1%, which is notably higher than the known values in silicon homojunction diodes. For temperature-dependent measurements of EL and dark I-V curves, one of the samples was cut into small-area (1 cm2) pieces. It was found that EL intensity as a function of temperature develops a maximum at T = 223 K. At low temperatures, the current at weak bias is shown to be due to tunneling mechanism. A theoretical model is developed that explains all these findings quantitatively.