Valence-band offset of epitaxial ZnO∕MgO (111) heterojunction determined by x-ray photoelectron spectroscopy

Abstract

The valence-band offset of ZnO / MgO ͑111͒ heterojunction has been directly measured by x-ray photoelectron spectroscopy. Excluding the strain effect, the valence-band offset is determined to be 0.87Ϯ 0.20 eV, and the conduction-band offset ⌬E C is deduced to be −3.59Ϯ 0.20 eV, indicating that ZnO / MgO heterojunction has a type-I band alignment. The conduction-band and valence-band offset of MgO / ZnO is used to interpret the origination of p-type conduction in undoped Mg x Zn 1−x O alloy and deeper acceptor level in undoped and N-doped p-type Mg x Zn 1−x O alloy than in ZnO.

Energy band alignment of SiO2/ZnO interface determined by x-ray photoelectron spectroscopy

“…1͑d͒, a value of VBM of 1.90Ϯ 0.10 eV is obtained by using the same method as SiO 2 . These values from the ZnO film are agreement with the results reported by Yao et al 27 The energy difference between Zn 2p 3/2 and VBM of the ZnO film ͑E Zn 2p 3/2 ZnO − E VBM ZnO ͒ is 1019.13 eV, which is also close to our previous reported results where the ZnO films were deposited by metal-organic chemical vapor deposition. 26 The CL spectra of Si 2p and Zn 2p 3/2 from the SiO 2 / ZnO interface are shown in Figs.…”

Fabrication of high-quality ZnCdO epilayers and ZnO/ZnCdO heterojunction on sapphire substrates by pulsed laser deposition

“…is determined to be 1018.307 eV, which is well consistent with the value of 1018.90 eV measured by Li et al [36] Similarly, the E ZnCdO…”

“…The VBM position relative to the surface Fermi level are obtained by linear extrapolation of the leading edge to the extended base line of the VB spectra with an energy reference of E ZnO VBM = 0 eV. This linear method has already been widely used to determine the VBM of semiconductors with an accuracy of about ±0.05 eV [35,36]. In addition, the Zn 2p 3/2 CL spectra were fitted to a Voigt (mixed Lorentzian-Gaussian) curve using a Shirley background and the binding energy for the CL peaks are taken as the energy corresponding to the maximum intensity.…”

Electrostatic tuning of Kondo effect in a rare-earth-doped wide-band-gap oxide

“…The synthesis procedures are similar to our previous reports on doped ZnO films. [12][13][14][15][16][17][18][19][20] During the growth process, the substrate temperature was fixed at 450…”