Abstract
ZnO and related alloys are promising materials for application in photonics, electronics, piezoelectric nanogenerators and electromechanical devices. In this work, a Valence Band Anti-Crossing (VBAC) model is developed to analyze the energy bandgap of ZnO binary compound when it is lightly alloyed with anion sulfur (S) material. Minority anion alloy ZnO l-x S x exhibits unusual bowing of energy bandgap compared to cation alloying. The energy bandgap decreases dramatically from 3.37 eV to approximately 2.65 eV as the S composition increases to 100%. The main reason of the energy bandgap reduction is found to be the increase (up-shift) of the valence band edge (VBE) due to interaction between ZnO's extended VBE and the localized S defect energy state. The VBE of ZnO host material spilt into two sub-bands, the upper band E-and the lower band E+, when the S atoms replace the O atoms. The overall computational model is based on a coupling of the Hamiltonian of the supercell based on a fully-atomistic 8-band Sp 3 tight-binding basis set including spin orbital interaction and the Valence Force-Field (VFF) model using Keating potentials for strain calculations.
| Original language | English |
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| Title of host publication | 2018 IEEE 13th Nanotechnology Materials and Devices Conference, NMDC 2018 |
| Publisher | Institute of Electrical and Electronics Engineers Inc. |
| ISBN (Electronic) | 9781538610169 |
| DOIs | |
| State | Published - 8 Jan 2019 |
| Externally published | Yes |
Publication series
| Name | 2018 IEEE 13th Nanotechnology Materials and Devices Conference, NMDC 2018 |
|---|
Bibliographical note
Publisher Copyright:© 2018 IEEE.
Keywords
- atomistic tight-binding
- band anti-crossing
- unusual bowing
- valence band edge
- valence force-field
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Instrumentation