InGaN laser diodes by molecular beam epitaxy

Semiconductor nitrides have many applications for optoelectronic devices; particularly, blue-violet laser diodes (LDs) are required for blu-ray optical disc systems. Molecular beam epitaxy (MBE) with its fine control of growth parameters and capability for in-situ growth monitoring is a well-established technique for depositing III-V heterostructures. Indeed, many commercial infrared LDs are grown very successfully by MBE. However, MBE-growth of nitrides is much more difficult, because providing enough nitrogen atoms at the growth surface, sustaining the high growth temperatures as well as finding the right growth parameters have proved to be very challenging. We recently reported the first InGaN LDs by MBE, showing that those problems can be solved in practice as well as demonstrating the capability of MBE to produce high-quality optoelectronic devices. As the efficiency of nitrides depends strongly on the growth process, structural differences of MBE over metal-organic vapor phase epitaxy (MOVPE)-material may also lead to device advantages. Our first InGaN LDs were grown on sapphire templates, with a pulsed room-temperature threshold current-density of 30 kA/cm