Abstract
Abstract We propose a simplified theoretical model that well reproduces the dispersion curves of the multiple subbands in a two-dimensional electron gas in the accumulation layer at the surfaces of wide-gap semiconductors. The electronic band structures containing multiple subbands with different orbital characteristics are derived by self-consistently solving the Poisson-Schrödinger equations with anisotropic effective mass approximations. Calculations were carried out on the two-dimensional electron gas states formed at the surfaces of SrTiO3 and ZnO for comparison. The calculated subband structures at the SrTiO3 surface were in excellent agreement with available angle-resolved photoelectron spectroscopy data, confirming the validity of the present model. The calculations further indicate the existence of a high electron density, exceeding 2 × 1021 cm-3 and a high electric field of 20 MVcm-1 at the surface. Moreover, photoelectron-escape depths are discussed quantitatively and photoelectrons from the first subband are found to dominate the total photoelectron intensity in the spectra.
Original language | English |
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Article number | 20565 |
Pages (from-to) | 224-230 |
Number of pages | 7 |
Journal | Surface Science |
Volume | 641 |
DOIs | |
Publication status | Published - 2015 Jul 25 |
Externally published | Yes |
Keywords
- 2D electron
- Space charge layer
- SrTiO
ASJC Scopus subject areas
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry