고려대학교 물리학과

2019 Spring Physics Colloquium 

III-V materials such as GaN, GaAs and InP are the most common materials for LEDs, lasers, and space solar cells. GaN LEDs have been replacing florescent light bulbs in our houses. GaAs-based VCSELs are the main components in the data center communications and in the iPhone’s face ID technology. Revolution of such materials growth and device design have enabled such disruptive technologies. This seminar will first present some of those crucial III-V photonic materials and devices. Then, I will show my previous works on epitaxial growth of InAs quantum dot lasers on silicon for next-generation telecom applications. The lasers show a very low threshold current, temperature-insensitivity, low reflection-sensitivity and ultra-small foot-print compared to the quantum well counterparts. Also, the underlying physical phenomena on the high performance quantum dot lasers on silicon will be explained. I will also show GaAs solar cells epitaxially grown on silicon with a certified AM 1.5G efficiency of 16.8%. A novel Ge/III-V nano heterostructure growth will be briefly presented as a new method for strain-engineered Ge nanostructures. Record-high 5.3% tensile-strained Ge nanowires are demonstrated by hosting them in InAlAs matrix using molecular beam epitaxy.