Growth and characterization of AlInN/GaN superlattices

Data are presented on near -lattice -matched Al1-xInxN/GaN superlattices (SLs) with superior morphology to thick AlInN layers. The SLs are grown by metalorganic chemical vapor deposition and consist of - 3 nm thick AlInN, -1 nm thick GaN layers, and x = 0.153 to 0.203. The SLs are grown with either 20 or 100 periods on GaN-onsapphire or free-standing GaN substrates. Growth conditions are explored, and the In -content of the AlInN layers within the SL increases with growth temperature and pressure, while the growth rate decreases with pressure. Thick AlInN layers grown on GaN-on-sapphire exhibit island growth with a root mean square (rms) roughness of - 0.65 nm, while the AlInN/GaN SLs have steplike morphology and rms - 0.3 nm. Also, 80 nm thick AlInN/GaN SLs grown on GaN substrates exhibit nearly perfect steplike morphology with a lower rms of - 0.13 nm and extremely low pit densities. The refractive index of the SLs is the weighted average of AlInN and GaN, and they emit light from the quantum states within the thin GaN layers. These AlInN/GaN SLs are a potential replacement for AlInN layers in optoelectronic and electronic devices that require steplike morphology and controlled pitting.