Transport and phototransport properties of plasma-deposited hydrogenated amorphous silicon nitrogen alloys, a-Si,N:H

Abstract

There are two potential applications for a-Si,N:H alloys in photovoltaic (PV) tadem devices (i) as a wide band gap photoactive i-region material, and (ii) as a heavily doped p-type window material. This paper addresses the first of these, discussing transport and phototransport properties of thin films deposited by remote plasma-enhanced chemical-vapor deposition. Chemical and structural properties have been characterized by infrared spectroscopy, high resolution transmission electron microscopy, and secondary ion mass spectrometry. Other measurements include the photo- and dark-conductivities, the optical absorption edge, and the minority carrier transport by the steady state photocarrier grating technique. Comparisons of the properties of a-Si,N:H alloys deposited from two different N-atom source gases, N2 and NH3 are presented. Significant increases in the slope of the optical absorption edge, and the magnitude of the Staebler–Wronski light-induced-degradation are identified for the films deposited from the NH3 source gas relative to those deposited from the N2 source gas.