Valence-band structure of InN from x-ray photoemission spectroscopy

Abstract

The valence-band structure of clean, high-quality, single-crystalline wurtzite InN thin films prepared with atomic hydrogen is investigated using x-ray photoemission spectroscopy. The In4d 5/2 semicore level due to the In-N bond is found to lie 16.0± 0.1 eV above the valence band maximum. Experimental valence-band spectra are compared with theoretical calculations of the valence-band density of states ͑VB-DOS͒, employing density functional theory within the local density approximation with quasiparticle and self-interaction corrections. Agreement between the experimental valence band spectrum and the theoretical VB-DOS is obtained.

Defect-induced room temperature ferromagnetism in un-doped InN film

“…One can see an apparent shoulder is added besides the main peak in In3d 5/2 spectrum. According to previous studies, 18,19 the peak around 444eV is attributed to In-N bonds and the other component (about 445.2eV) is ascribed to In-O bond. In the N 1s photoelectron energy region, two components are also identified.…”

Morphology and surface electronic structure of MBE grown InN

“…Photoemission spectroscopy (ultraviolet photoelectron spectroscopy, UPS and X-ray photoelectron spectroscopy, XPS) is a powerful tool to investigate the electron valence band DOS in the near surface region to validate theoretical calculations of the band structure [8]. Information on the surface properties of indium nitride, especially the electronic structure, is rather rare.…”

Electronic structure of InN studied using soft x-ray emission, soft x-ray absorption, and quasiparticle band structure calculations

“…Recently, the first combined x-ray photoemission spectroscopy (XPS) measurements and density functional theory (DFT) calculations of the valence band structure of single crystalline wurtzite InN have been reported. 3 Studies of well prepared polar InN samples using both high resolution angle resolved photoemission spectroscopy (ARPES) and high resolution electron energy-loss spectroscopy revealed significant electron accumulation near the film surface, leading to quantum well states in a layer extending from the surface up to 80Å below it. 4 Recent calculations have reported that the microscopic origin of the intrinsic electron accumulation at well-prepared polar InN surfaces is due to In-In bonds, within the In bilayer reconstruction, resulting in surface states above the conduction band minimum.…”

“…3 Furthermore, XES provides a direct measurement of the hybridization of shallow metal d-orbitals with ligand p-orbitals. 9 Since the x-ray fluorescence process is weak compared to the competing non-radiative deexcitation channels, 12 a larger monochromator slit width is required to acquire reasonable counting statistics of 30/sec.…”

“…16 The present approach goes beyond previously reported calculations since it is independent of the experimental d-band binding energy and provides access to the d-states DOS. 3 All calculations were performed using the Vienna Ab initio Simulation Package (VASP). 17 The calculated band gap was found to be 0.71 eV.…”