Abstract
In this work, we demonstrate that the optical bandgap of WO3 films can be continuously controlled through uniaxial strain induced by low-energy helium implantation. The insertion of He into epitaxially grown and coherently strained WO3 films can be used to induce single axis out-of-plane lattice expansion of up to 2%. Ellipsometric spectroscopy reveals that the optical bandgap is reduced by about 0.18 eV per percent expansion of the out-of-plane unit cell length. Density functional theory calculations show that this response is a direct result of changes in orbital degeneracy driven by changes in the octahedral rotations and tilts.
Original language | English |
---|---|
Article number | 066106 |
Journal | APL Materials |
Volume | 5 |
Issue number | 6 |
DOIs | |
State | Published - Jun 1 2017 |
Funding
This work was supported by the DOE Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division and the Office of Science Early Career Research Program. This research was in part conducted at the Center for Nanophase Materials Sciences, which is a U.S. Department of Energy (DOE), Office of Science User Facility, and used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231.