Ge–Sn semiconductors for band-gap and lattice engineering

Abstract

We describe a class of Si-based semiconductors in the ${\mathrm{Ge}}_{\text{1−x}}{\mathrm{Sn}}_x$ system. Deuterium-stabilized Sn hydrides provide a low-temperature route to a broad range of highly metastable compositions and structures. Perfectly epitaxial diamond-cubic ${\mathrm{Ge}}_{\text{1−x}}{\mathrm{Sn}}_x$ alloys are grown directly on Si(100) and exhibit high thermal stability, superior crystallinity, and crystallographic and optical properties, such as adjustable band gaps and lattice constants. These properties are completely characterized by Rutherford backscattering, low-energy secondary ion mass spectrometry, high-resolution transmission electron microscopy, x-ray diffraction (rocking curves), as well as infrared and Raman spectroscopies and spectroscopic ellipsometry. Ab initio density functional theory simulations are also used to elucidate the structural and spectroscopic behavior.