Solid-phase synthesis of Mg₂Si thin film on sapphire substrate

Abstract

Magnesium silicide (Mg2Si) is expected as a semiconductor material for thermoelectric devices though synthesis of the thin film has been difficult due to difference in thermodynamic properties of Mg and Si. The authors have succeeded in preparing a poly-crystalline Mg2Si thin film with a thickness of ~1m and strong (111) orientation on a sapphire substrate (r plane). The method includes sputter deposition of a Mg/Si bilayer from independent Mg and Si sources and post-annealing (2 h) in argon gas at 900 Pa. The optimum annealing temperature for the Mg2Si film synthesis is found to be 300-400°C.

Observation of Magnesium-Induced Crystallization (Mg-MIC) of a-Si Thin Film

“…The authors have been devoted to prepare a poly-crystalline Mg 2 Si thin film by annealing a sputter-deposited amorphous Mg/Si bilayer in argon gas atmosphere. In this study, the growth of poly-crystalline Mg 2 Si was identified in the temperature range from 300 ˚C to 400 ˚C [4]. Recently, the authors observed that the Raman peak at 253 cm -1 typical of Mg 2 Si [3] disappeared and the peak at 520 cm -1 typical of poly-Si [5] newly appeared at the temperature higher than 450 ˚C.…”

Fine structural and photoluminescence properties of Mg2Si nanosheet bundles rooted on Si substrates

“…It has also been reported that the peaks shifts to higher energies under pressure. 42) For thin films or layered Mg 2 Si, peaks have been observed at 253, 344, 43) 257, 348, 44) 252, and 328 cm −1 . 45) A red-shift in the Raman peak due to the size effects has been reported for nanocrystals.…”