Role of ion bombardment and plasma impedance on the performances presentedby undoped a-Si : H films

The aim of this paper was to present results of the role of the d.c. grid b ias on the silane plasma impedance and its I-V characteristics to grow undo ped amorphous silicon (a-Si:H) films by plasma enhanced chemical vapour dep osition (PECVD) in conditions where some nanoparticles can be formed in the growth region of the deposition process, under proper ion bombardment. The results achieved show that the performances of the films produced are depe ndent on the self bias voltage that can present photosensitivities of appro ximately 10(7) (two orders of magnitude larger than the one exhibited by fi lms grown under conventional conditions) with density of states determined by the constant photocurrent method below 4 x 10(15) cm(-3). Apart from tha t, the films grown are less affected by light soaking than the conventional films. (C) 2001 Elsevier Science B.V. All rights reserved.