Growth of vertical cavity surface emitting laser material on (3 1 1)B GaAs by MBE

Abstract

We report on the growth of VCSEL structures on (3 1 1)B GaAs substrates. For the growth of AlGaAs and AlAs, the best morphology and material quality were obtained for growth temperatures > 650°C. Surface morphology and mirror reflectivity degraded significantly at low growth temperatures ( < 600°C). From low-temperature photoluminescence (LTPL), we found a forbidden temperature range for the growth of InGaAs quantum well-active regions on (3 1 1)B substrates between 540 and 560°C. Active region growth temperatures in this range showed low intensity, broad LTPL, and poor laser characteristics. Cross-section TEM measurements show poor homogeneity for material grown in this temperature range. At higher temperatures (580°C), In desorption is greatly increased, so < 520°C was selected as the optimal growth temperature. Even with a non-optimized structure, the first reported VCSELs on (3 1 1)B were fabricated with a pulsed J th = 9 kA/cm 2 at - 40°C and 28 kA/cm 2 at room temperature. At - 40°C, 10 nW of SHG blue light at 485 nm was detected under pulsed conditions, and 2 nW was detected under CW conditions and was visible to the naked eye. By improving the structure we obtained CW lasing at room temperature with 300 A/cm 2 as a broad area laser and 1.4 kA/cm 2 as a VCSEL. A maximum power of 0.55 nW at 490 nm was detected CW at room temperature.