High-mobility AlGaN/GaN heterostructures grown on sapphire by metal-organic chemical vapor deposition

High-quality AlGaN/GaN heterostructures were grown on sapphire by metal-organic chemical vapor deposition (MOCVD). The factors limiting electron mobility were also investigated using atomic force microscopy, photoluminescence and capacitance-voltage measurements. An unintentionally doped Al0.11Ga0.89N/GaN heterostructure showed two-dimensional electron gas (2DEG) mobilities of 12000 and 9400 cm(2)/V s at 9 and 77 K, respectively, which are higher than the previously reported values for the same structure grown on either SiC or sapphire by MOCVD. In addition, we found that the 2DEG mobility can be enhanced by increasing the AlGaN layer thickness.