Molecular beam epitaxy of IV–VI mid-infrared vertical cavity surface-emitting quantum well laser structures

Abstract

PbSe/PbSrSe multiple quantum well vertical cavity surface-emitting laser (VCSEL) structures were successfully grown by molecular beam epitaxy on freshly cleaved BaF2(111) substrates. In situ reflection high-energy electron diffraction characterizations demonstrated high quality active layer growth of the VCSEL structure. Three-stack Pb0.97Sr0.03Se/BaF2 distributed Bragg reflector renders reflectivity as high as 99%. Top mirror with 35% Sr/PbSe flux ratio was grown for the first time to allow 1.064 Nd:YAG pumping. The transition energies of PbSe/PbSrSe multiple quantum wells that were employed as active layers were determined by both photoluminescence and differential Fourier transform infrared transmission spectra. The combined measurements of reflectance and photoluminescence show good alignment of the gain peak of PbSe/Pb0.97Sr0.03Se multiple quantum well (MQW) active layers to the cavity resonance. Above-room-temperature pulsed emission at lasing wavelength of λ=4.1 μm was observed.