Continuously Controlled Optical Band Gap in Oxide Semiconductor Thin Films
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- 作者：Andreas Herklotz ; Stefania Florina Rus ; Thomas Zac Ward
- 刊名：Nano Letters
- 出版年：2016
- 出版时间：March 9, 2016
- 年：2016
- 卷：16
- 期：3
- 页码：1782-1786
- 全文大小：321K
- ISSN：1530-6992
文摘
The optical band gap of the prototypical semiconducting oxide SnO2 is shown to be continuously controlled through single axis lattice expansion of nanometric films induced by low-energy helium implantation. While traditional epitaxy-induced strain results in Poisson driven multidirectional lattice changes shown to only allow discrete increases in bandgap, we find that a downward shift in the band gap can be linearly dictated as a function of out-of-plane lattice expansion. Our experimental observations closely match density functional theory that demonstrates that uniaxial strain provides a fundamentally different effect on the band structure than traditional epitaxy-induced multiaxes strain effects. Charge density calculations further support these findings and provide evidence that uniaxial strain can be used to drive orbital hybridization inaccessible with traditional strain engineering techniques.