Structure, morphology and electrical properties of Mg2Si layers deposited by pack cementation

Abstract

Magnesium silicide (Mg2Si) is a promising narrow gap semiconductor which can be used as a thermoelectric material. Chemical vapor deposition by pack cementation, which is a simple and low cost technique, was used for the first time in this work for the formation of Mg2Si compound. A series of experiments were carried out at temperatures 500–650°C with different deposition times ranging between 15 and 180min. As a result single phase thick layers have been prepared, depending on growth temperature and deposition time. Mg2Si was formed as a result of the Mg diffusion into the Si matrix while the film thickness increased with the deposition time, and temperature. Electrical and optical properties of the grown layers have been investigated. The examination of the as formed material was completed by performing thermal stability tests, for the determination of the safe service temperature range of the coupons. From all the experimental outcomes, it is concluded the optimum conditions for the formation of Mg2Si films is at 650°C for a 180min deposition period.