Polarization modulation of nanotrenches in GaN (0001)/(000(1)over-bar) by surface hydrogenation

Using first-principles total-energy calculations within the framework of the density functional theory, we show that nanometer-scale trenches excavated in GaN with (0001) and (000 (1) over bar) surfaces cause a variable electrostatic potential difference, which is tunable by controlling the hydrogen coverage of the surfaces. A positive potential difference of 3.53V is induced between clean (0001) and (000 (1) over bar) surfaces in nanotrenches, while a negative potential difference of % 5.93V is induced in nanotrenches with fully hydrogenated surfaces. The value of the potential difference strongly depends on the H coverage of the surfaces. Nanotrenches excavated in GaN with polar surfaces can supply electricity for various nanoscale devices consisting of molecules, clusters, and atoms inserted into the trenches. (C) 2017 The Japan Society of Applied Physics