Selective etching of GaN polar surface in potassium hydroxide solution studied by x-ray photoelectron spectroscopy

Abstract

Etching characteristics of nondoped GaN films with the polar surface in KOH solution have been investigated. It is confirmed that the continuous etching in KOH solution takes place only for the GaN films with N-face (Ϫc) polarity independent of the deposition method and growth condition. It is found by x-ray photoelectron spectroscopy ͑XPS͒ analysis for the Ga face (ϩc) and N-face (Ϫc) GaN films that the atomic composition of the ϩc surface is not changed before and after dipping in KOH solution and that on the other hand, the amount of oxygen ͑oxide͒ on the Ϫc surface is significantly decreased by the etching. It is also found that the band bending increases by Ϫ0.4Ϯ0.2 and 0.6Ϯ0.2 eV for the ϩc and Ϫc surfaces after etching, respectively. This is discussed in terms of the surface chemistry. Based on the XPS result, the selective etching of the GaN polar surface is pointed out to originate from bonding configuration of nitrogen at the surface.

Effect of the ammoniating time on microstructure and morphology of one-dimensional Mg-doped GaN nanowires catalysed with Au

“…As observed in Figure 2(c), the energy peak for N1s is centred at 397.3 eV, instead of 399 eV (binding energy of N element existing as atomic style), similar to the results of Li (397.4 eV) [17] and Veal (397.6 eV) [18], i.e. the N atom exists as a nitride.…”

Substrate temperature influence on the properties of GaN thin films grown by hollow-cathode plasma-assisted atomic layer deposition

“…2(d)] obtained for GaN grown at 450 C was fitted similarly using two subpeaks located at 397.49 and 395.67 eV, corresponding to N-Ga and Auger Ga bonds, respectively. 12,16 As the deposition temperature increases, the Ga 3d and N 1s binding energies (BEs) shifted from lower BE to the higher BE. The shift in the Ga 3d and N 1s core levels was observed to be 1 eV.…”

Low-resistance Ni-based Schottky diodes on freestanding n-GaN

“…It has been shown that the Ga plane remains inert in aqueous KOH treatment but that the surface chemistry is affected, leading to a potential change in the band bending. 15 KOH treatment also results in a smooth surface. A large area Ohmic contact was formed on the substrate ͑N face͒ by electron beam evaporated Ti/ Al/ Pt/ Au ͑3 / 50/ 30/ 200 nm͒ to complete the fabrication of the vertical geometry diodes.…”