UC Santa Barbara

The MOCVD growth mechanism of InAs QD was first explored. By optimizing the InAs QD growth parameters, including growth temperature, V/III, growth rate, and capping process, highly uniform QDs have been achieved with a dot density of about 5.5E10cm-2. Room temperature PL characterization on the QDs shows a 50 nm FWHM for the ground state. A high-quality InGaP thick layer under low temperatures was also developed as the cladding layer for the laser structure. High-performance FP cavity QD laser on GaAs substrate was first demonstrated with state-of-the-art performance. The broad-area laser without facet coating shows a single facet power of 200 mW; the short narrow-ridge laser without facet coating shows a high wall-plug efficiency of about 30%. To enable a QD laser on Si, the GoVS template was developed. Combining the technology of aspect ratio trap, thermal cycle annealing, and strain layer superlattice, the GoVS sample has achieved a low threading dislocation density (4E6cm-2) and a surface roughness of 2.7 nm. The full laser structure was grown on the GoVS sample with AlGaAs as the lower cladding layer and low-temperature InGaP as the upper cladding layer. The laser on Si has shown a decent device performance at room temperature and continuous-wave operation.