In this work we study the growth mechanisms of InGaN in plasma-assisted molecular beam epitaxy (PAMBE). We investigate growth of InGaN layers on vicinal GaN (0001) substrates. Indium incorporation as a function of gallium and nitrogen fluxes was examined. We propose microscopic model of InGaN growth by PAMBE postulating different indium adatom incorporation mechanisms on two nonequivalent atomic step edges of wurtzite crystal. The different roles of gallium and nitrogen fluxes during the growth of InGaN layers is discussed.
We present recent progress in the growth of nitride based laser diodes (LDs) made by Plasma Assisted Molecular Beam Epitaxy (PAMBE). In this work we demonstrate LDs grown by PAMBE operating in the range 450 – 460 nm. The LDs were grown on c-plane bulk GaN substrates with threading dislocation density (TDD) ranging from 103 cm-2 to 104 cm-2. The low TDD allowed us to fabricate cw LDs with the lifetime exceeding 2000 h at 10 mW of optical output power. The maximum output power for 3 LDs array in cw mode was 280 mW and 1W in pulse mode. The low temperature growth mode in PAMBE allow for growth of AlGaN-free LDs with high In content InGaN waveguides. The key element to achieve lasing wavelengths above 450 nm was the substantial increase of the nitrogen flux available during the growth by PAMBE.