Photocurrent response times in undoped amorphous hydrogenated silicon

Abstract

The influence of electrical contacts upon coplanar electrode photocurrent response times has been explored in undoped amorphous hydrogenated silicon (a‐Si:H) by measuring contact‐induced photocurrents in a virtual ground plane. The results indicate that the relatively long photocurrent response times observed in undoped a‐Si:H cannot be attributed to contacts. The response times are evidence that some deep‐lying defects in a‐Si:H are true electron photocarrier traps and not recombination centers. The discrepancy between long‐time coplanar and time‐of‐flight transient photocurrent measurements upon undoped a‐Si:H remains unresolved.