UVB-emitting InAlGaN multiple quantum well synthesized using plasma-assisted molecular beam epitaxy

• Published in: AIP advances Vol. 7; no. 3; pp. 035109 - 035109-7
• Main Authors: Kong, W., Roberts, A. T., Jiao, W. Y., Fournelle, J., Kim, T. H., Losurdo, M., Everitt, H. O., Brown, A. S.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01-03-2017; AIP Publishing LLC
• Subjects: Atomic force microscopy; Chemical synthesis; Computer simulation; Dislocation density; Emissions control; Molecular beam epitaxy; Molecular structure; Multi Quantum Wells; Photoluminescence; Radiative recombination; Spectroellipsometry; Thin films; X ray spectra; X-ray diffraction
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.4973637

A high Al-content (y > 0.4) multi-quantum-well (MQW) structure with a quaternary InxAlyGa(1-x-y)N active layer was synthesized using plasma-assisted molecular beam epitaxy. The MQW structure exhibits strong carrier confinement and room temperature ultraviolet-B (UVB) photoluminescence an order of magnitude stronger than that of a reference InxAlyGa(1-x-y)N thin film with comparable composition and thickness. The samples were characterized using spectroscopic ellipsometry, atomic force microscopy, and high-resolution X-ray diffraction. Numerical simulations suggest that the UVB emission efficiency is limited by dislocation-related non-radiative recombination centers in the MQW and at the MQW - buffer interface. Emission efficiency can be significantly improved by reducing the dislocation density from 109cm−2 to 107cm−2 and by optimizing the width and depth of the quantum wells.