Research progress in the epitaxial growth of silicon-based group IV materials, and their light emitters and photodetectors

Silicon-based optoelectronic integrated circuits, which are composed of silicon-based light sources, photodetectors, light modulators, and other modules, are core technologies in the recent information era. Silicon is the cornerstone of microelectronic integration, but it encounters issues with optoelectronic integration. First, as an indirect bandgap material, silicon is difficult to be used in high-efficiency light sources, which is still currently the biggest challenge. Second, the absorption coefficient of silicon in the near-infrared communication band is very low, so it is not suitable for the near-infrared photodetectors. Silicon-compatible group IV materials can achieve direct band through band engineering. They have a high absorption coefficient in the near-infrared and have attracted extensive attention of researchers. In this paper, the research progress of epitaxial growth of silicon-based materials, and their light emitters and photodetectors, are reviewed. The growth technologies of Ge, SiGe/Ge heterojunction, quantum wells, and GeSn quantum dots are introduced. Based on the above silicon-based group IV heterostructure materials, a new method for modulating the height of the contact barrier between metal and semiconductor was proposed. Also, various photodetectors with different structures were developed. The lateral heterojunction LED and vertical resonant-cavity LED, including dual active regions compatible with traditional CMOS processes, were developed. The luminescence performance of the devices was improved effectively and the luminescence gain of strain Ge was observed.