Low dislocation GaN via defect-filtering, self-assembled SiO2-sphere layers.

Wang, George T. ; Li, Qiming

Sandia National Laboratories

关键词: Gallium Nitrides;    Solid State Electronics.;    Quantum Efficiency;    Gallium Nitride-Electric Properties.;    36 Materials Science;   

DOI  :  10.2172/973848
RP-ID  :  SAND2009-6153
RP-ID  :  AC04-94AL85000
RP-ID  :  973848

美国|英语

来源: UNT Digital Library

【 摘 要 】

The III-nitride (AlGaInN) materials system forms the foundation for white solid-state lighting, the adoption of which could significantly reduce U.S. energy needs. While the growth of GaN-based devices relies on heteroepitaxy on foreign substrates, the heteroepitaxial layers possess a high density of dislocations due to poor lattice and thermal expansion match. These high dislocation densities have been correlated with reduced internal quantum efficiency and lifetimes for GaN-based LEDs. Here, we demonstrate an inexpensive method for dislocation reduction in GaN grown on sapphire and silicon substrates. This technique, which requires no lithographic patterning, GaN is selectively grown through self-assembled layers of silica microspheres which act to filter out dislocations. Using this method, the threading dislocation density for GaN on sapphire was reduced from 3.3 x 10{sup 9} cm{sup -2} to 4.0 x 10{sup 7} cm{sup -2}, and from the 10{sup 10} cm{sup -2} range to {approx}6.0 x 10{sup 7} cm{sup -2} for GaN on Si(111). This large reduction in dislocation density is attributed to a dislocation blocking and bending by the unique interface between GaN and silica microspheres.