Improved mobility in InAlN/AlGaN two-dimensional electron gas heterostructures with an atomically smooth heterointerface

We attempted to improve the mobility of InAlN/AlGaN two-dimensional electron gas (2DEG) heterostructures by achieving an atomically smooth heterointerface in metalorganic chemical vapor deposition processes. In the result, it was confirmed that the high-growth-rate AlGaN layer was very effective to improve the surface morphology. The atomically smooth surface morphology with a root-mean-square roughness of 0.26 nm was achieved for an Al0.15Ga0.85N layer under the growth rate of approximately 6 mu m/h. Furthermore, nearly lattice-matched In0.17Al0.83N/Al0.15Ga0.85N 2DEG heterostructures with the atomically smooth heterointerface exhibited a 2DEG mobility of 242 cm(2) V-1 s(-1) with a 2DEG density of 2.6 x 10(13)/cm(2), which was approximately 1.5 times larger than the mobility in a sample grown under original conditions. (C) 2018 The Japan Society of Applied Physics.