A diagnostic tool for analyzing the current-voltage characteristics in a-Si/c-Si heterojunction solar cells

Understanding the effects of device parameters on carrier transport is essential for the design of high efficiency aSi/c-Si heterojunction solar cells. It is well known that the dark current-voltage (I-V) characteristics are correlated to fundamental PV parameters that dictate cell performance, and therefore an analysis of dark I-V may be a useful diagnostic tool to monitor changes in the device parameters (indirectly correlated to solar cell efficiency). In this paper, we first measure and then interpret the forward bias dark I-V characteristics of a-Si/c-Si solar cells by numerical and analytical models. Several well-known (but poorly understood) features of dark I-V characteristics are shown to be correlated to parameters of fundamental interest to solar cell design and can therefore be used as important markers of device parameter variation during the development process.