GERMANIUM-TIN PHOTO DETECTORS FOR APPLICATIONS IN THE TWO MICRON WAVELENGTH RANGE

Abstract

GeSn has emerged as a promising material for development of optoelectronics devices. This thesis focuses on the design and demonstration of GeSn photo detectors and micro-structures for photonics applications mainly focusing on 2 μm wavelength range. First, a GeSn photo detector on insulator with extended detection capability up to 2 μm and a decent bandwidth of 715 MHz was demonstrated, which is attractive for 3D integration. Second, high speed photo detection at 2 μm with bandwidth larger than 10 GHz was achieved using a GeSn/Ge multiple-quantum-well (MQW) photodiode design. Third, to develop 2 μm integrated photonics, the GeSn MQW photodiode was integrated onto a GeOI CMOS photonics platform, enabling the integration of photonics with advanced Ge CMOS devices. Finally, GeSn micro-structures for lasing applications were explored. GeSn micro-disk resonant cavity was designed and fabricated on insulator substrate. GeSn micro-bridge was also investigated with strain engineering toward achieving a GeSn laser.