Hexagonal Si-Ge Class of Semiconducting Alloys Prepared by Using Pressure and Temperature.

Abstract

Multi-anvil and laser-heated diamond anvil methods have been used to subject Ge and Si mixtures to pressures and temperatures of between 12 and 17 GPa and 1500-1800 K, respectively. Synchrotron angle dispersive X-ray diffraction, precession electron diffraction and chemical analysis using electron microscopy, reveal recovery at ambient pressure of hexagonal Ge-Si solid solutions (P63 /mmc). Taken together, the multi-anvil and diamond anvil results reveal that hexagonal solid solutions can be prepared for all Ge-Si compositions. This hexagonal class of solid solutions constitutes a significant expansion of the bulk Ge-Si solid solution family, and is of interest for optoelectronic applications.