Pulsed laser deposition of photosensitive a-Si thin films

Si films have been fabricated by pulsed KrF excimer laser deposition (PLD) through the use of various Si targets and deposition conditions. The deposits consisted of droplets and homogeneous films, which were assigned to be crystalline and amorphous silicon, respectively, by the micro Raman scattering measurements. Not only the crystalline but also the amorphous Si part scarcely (<1 atomic %) contained hydrogen regardless of whether or not the films are prepared in the presence of H2 gas. Conditions were explored to reduce the droplet formation and to produce photosensitive films. Amorphous Si films with photosensitivity (σph/σd) exceeding 103 were obtained, and they exhibited high stability against light soaking. Thus, PLD is a promising method to fabricate photosensitive and photostable a-Si films.