Engineering of AlGaN-Delta-GaN Quantum-Well Gain Media for Mid- and Deep-Ultraviolet Lasers

The gain characteristics of AlGaN-delta-GaN quantum wells (QWs) with varying delta-GaN positions and AlGaN QW compositions are analyzed. The use of optimized AlGaN-delta-GaN QWs resulted in ~ 7-times increase in material gain over that of conventional AlGaN QWs for gain media emitting at ~ 240 nm. By employing asymmetric AlGaN-delta-GaN QWs, the optimized optical gain can be achievable for AlGaN-delta-GaN QW structure with realistic design applicable for mid- and deep-ultraviolet (UV) lasers. The threshold properties and differential gains are also studied for optimized AlGaN-delta-GaN QWs UV lasers.