Optically-pumped 285 nm edge stimulated emission from AlGaN-based LED structures grown by MOCVD on sapphire substrates

• Published in: Japanese Journal of Applied Physics 2014-11, Vol.53 (11), p.112101
• Main Authors: Lachab, Mohamed, Asif, Fatima, Coleman, Antwon, Ahmad, Iftikhar, Zhang, Bin, Adivarahan, Vinod, Khan, Asif
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/JJAP.53.112101

285 nm stimulated emission (SE) is demonstrated at room temperature from optically-pumped AlGaN multiple quantum wells (MQWs) deposited between a Si-doped AlGaN current spreading layer and a 25 nm Mg-doped p-type AlGaN clad layer. The epitaxial structures were grown by low pressure metalorganic chemical vapor deposition (MOCVD) on high-quality AlN/sapphire templates and a pulsed ArF excimer laser was used as the excitation source for lasing experiments. The threshold power density (Pth) was measured to be 970 kW/cm2 and the SE was strongly polarized in transverse electric (TE) mode. The minimum emission linewidth was ∼2 nm. The high value of Pth is primarily attributed to optical losses due to pump laser absorption in the top p-AlGaN. Our results show the viability of the MOCVD growth technology in conjunction with c-plane sapphire substrates to develop electrically-pumped deep-UV laser diodes.