Preparation and properties of Arsenic thin films deposited by Mercury-photosensitized chemical vapor deposition

Abstract

Deposition of arsenic thin films on quartz substrates utilizing mercury-photosensitized decomposition of arsine is reported. The deposition process is discussed and a simple model is proposed suggesting that the rate-limiting step in the deposition process involves the collision between the excited mercury atoms and arsine molecules. In addition, the arsenic thin films obtained using this technique are characterized utilizing X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, optical absorption and cold vapor atomic absorption spectrometry. Results of this characterization indicate minor differences in the optical absorption spectra for the amorphous arsenic thin films deposited by means of Hg-photosensitization as opposed to films obtained by sputtering or evaporation. In this work, rhombohedral arsenic thin films were obtained at a substrate temperature of 240°C and amorphous films were obtained at substrate temperatures less than 150°C.