STTR Phase I: Advanced Si-Ge-Sn-based Photonic Materials and Devices

This Small Business Technology Transfer (STTR) Phase I research project aims to demonstrate prototype infrared light detectors and photovoltaic (solar cell) devices based on technology developed at Arizona State University. The new technology to be explored consists in growing optical-quality alloys of tin and germanium (Ge1-ySny) directly on silicon wafers. These alloys act as infrared materials, and they can also be used as templates for the subsequent growth of other semiconductors on silicon. Of particularinterest for this project is the ternary alloy Ge1-x-ySixSny, grown for the first time at Arizona State University. Using this technology, it should be possible to build infrared detectors covering a spectral range previously inaccessible to silicon-based detectors, and to build multijunction photovoltaic devices for a more efficient capture of solar photons. The fabrication of semiconductor devices on cheap silicon wafers is of great significance because of the potentially enormous cost reductions and the possibility of integrating optoelectronic and microelectronic functions, which further reduces costs and contributes to system miniaturization. The infrared detectors proposed here cover the so-called telecom C-,L-, and U-bands within the wavelength window around 1500 nm, a region of great interest to the telecommunications industry. In the photovoltaics arena, the proposed devices have the potential to offer increased efficiencies to make crystalline silicon-based devices competitive with amorphous silicon solutions.