Growth and characterization of in _x Ga_1-x N multiple quantum wells without phase separation

Efficient conversion of photon energy into electricity is a crucial step toward a sustainable solar-energy economy. Likewise, solid-state lighting devices are gaining prominence because of benefits such as reduced energy consumption and reduced toxicity. Among the various semiconductors investigated, In _x Ga_1-x N alloys or superlattices are fervently pursued because of their large range of bandgaps between 0.65 eV and 3.4 eV. This paper reports on the fabrication of multiple quantum wells on LiGaO ₂ (001) substrates by plasma-assisted molecular beam epitaxy. Metal modulated epitaxy was utilized to prevent formation of metal droplets during the growth. Streaky patterns, seen in reflection high-energy electron diffraction, indicate two-dimensional growth throughout the device. Postdeposition characterization using scanning electron microscopy also showed smooth surfaces, while high-resolution x-ray diffraction and high-resolution transmission electron microscopy confirm the epitaxial nature of the overall quantum well structure.