Steady-state mobility lifetimes and photoconductivity in a-SiGe:H thin films

Abstract
The steady‐state mobility‐lifetime products (ημτ) and photoconductivity spectra of a‐Si:H and a‐SiGe:H films with band gaps from 1.74 to 1.10 eV have been determined. The importance of obtaining the bulk ημτ at an appropriate wavelength for films of differing compositions and absorption spectra is demonstrated. We show that ημτ measured at a wavelength such that the absorption‐thickness product is unity (αt=1) is proportional to the standard photoconductivity measured at one sun illumination for films having a wide range of band gaps and deposition conditions.