Polarization induced three-dimensional hole gas in compositionally graded InxGa1−xN layer

Abstract

A polarization-induced three-dimensional hole gas (3DHG) was demonstrated in undoped and compositionally graded InxGa1−xN layers. All samples were grown on Ga-face bulk GaN substrates by metal organic chemical vapor deposition. A high hole concentration of 2.8 × 1018 cm−3 was obtained in a 100-nm-thick InxGa1−xN layer where the indium composition was graded from x = 0 to x = 0.2. 3DHG density control by varying the indium composition and thickness of a compositionally graded InxGa1−xN layer was also demonstrated.