Proposal and physics of AlInN-delta-GaN quantum well ultraviolet lasers

The use of AlInN-delta-GaN quantum wells (QWs) active region for ultraviolet (UV) laser with wavelength (λ) ∼ 250–300 nm was proposed and investigated in this work. The design of active region consists of 24 Å staggered Al_0.91In_0.09N/Al_0.82In_0.18N layers with a 3 Å lattice-matched GaN delta layer, which enables dominant conduction band (C) to heavy hole (HH) subband transition. In addition, the insertion of the ultra-thin delta GaN layer will strongly localize the electron-hole wave functions toward the center of the QW, which leads to large transverse electric (TE) polarized optical gain. In comparison to the use of a conventional AlGaN QW system, the proposed AlInN-delta-GaN QW structure results in ∼3 times improvement in TE-gain at 255 nm. By tuning the delta-GaN thickness, the TE-polarized optical gain up to 3700 cm⁻¹ can be obtained for λ ∼ 280–300 nm, which is very promising to serve as an alternative active region for high-efficiency UV lasers.