Asymmetries in Amorphous Silicon Devices

Abstract

ABSTRACTThe consequences of the asymmetries in the density of electronic states of hydrogenated amorphous silicon on the behavior of electronic devices are discussed. Asymmetries in the relative widths of valence and conduction bandtails, the position of the dangling-bond states within the gap, and the occupation statistics of non-correlated defects are shown to affect the performance of p-i-n solar cells, and explain their superior performance and stability when compared with such devices illuminated through the n-layer (n-i-p). The device-modeling concepts which emerge help explain the differences between cell degradation via light exposure under various bias conditions, and cell degradation by dark forward bias.