Room-temperature deep-ultraviolet lasing at 241.5 nm of AlGaN multiple-quantum-well laser

TLDR

The laser cavity consisted of a cleaved facet of AlGaN epitaxial layers on a SiC substrate, requiring wafer polishing to a thickness of 60–70 µm for optimal cleaving. Room‑temperature deep‑ultraviolet lasing of AlxGa1−xN multiple‑quantum‑well lasers with x = 0.66 was achieved at 241.5 nm under pulsed optical pumping, with a threshold power of ~1200 kW/cm²; the shortest lasing wavelength was 231.8 nm at 20 K, and the wavelength shifts with temperature at 0.01 nm/K (20–150 K) and 0.03 nm/K (160 K–room temperature).

Abstract

Room-temperature deep-ultraviolet lasing of AlxGa1−xN multiple-quantum-well lasers with an Al composition x of 0.66 was achieved at 241.5 nm under pulsed optical pumping. The threshold pumping power was approximately 1200 kW/cm2 at room temperature. The shortest lasing wavelength was 231.8 nm at 20 K. The laser structure was grown on a high-quality AlN layer, which was grown on a 4H-SiC substrate by inserting an AlN/GaN multibuffer-layer structure between the substrate and the AlN layer. Temperature dependence of lasing wavelength was also estimated to be 0.01 and 0.03 nm/K in the temperature region from 20 to 150 K and from 160 K to room temperature, respectively. The laser cavity was made of a cleaved facet of AlGaN epitaxial layers and a SiC substrate. For this purpose, it was necessary to polish the wafer to a thickness of less than 100 μm. The optimal wafer thickness for cleaving in our experiments was 60–70 μm.