UV-C whispering-gallery modes in AlN microdisks with AlGaN-based multiple quantum wells on Si substrate

We have successfully fabricated 7-mu m 155-nm-thick undercut microdisk cavities with AlN/Al-0.60 Ga0.40N (5.5 nm/2.5 nm) multiple quantum wells epitaxially grown on Si substrate by metal-organic chemical vapor deposition. Upon optical pumping, whispering-gallery modes (WGMs) with wavelengths around similar to 250 nm can be observed throughout the photoluminescence spectrum at room temperature, with quality factors around 500 to 1000. These cavity modes have been analyzed by theoretical calculations. Our results suggest great potentials to demonstrate WGM lasing in the UVC range from these AlGaN/AlN-on-Si microdisk cavities monolithically grown on a Si platform. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)