Unraveling the properties of novel Ga2O3 nanolayers
ORAL
Abstract
Ga2O3 is a wide-band-gap semiconductor with promising applications in transparent electronics and in power devices. It is not a layered material in bulk, but nevertheless nanolayers can be produced by exfoliation [1]. First-principles calculations based on hybrid functionals show that there is seemingly an absence of quantum confinement in the Ga2O3 nanolayers: the calculated nanolayer band gap, independent of thickness, is equal to the bulk band gap.
This lack of quantum confinement is due to the presence of a compensating effect: the interaction between surface states on both sides of the nanolayer. The lowest two conduction bands have surface character, and these states interact through the nanolayer, inducing a splitting that almost exactly compensates the quantum confinement. The midpoint between these bands does show the effect of quantum confinement, as do the higher conduction-band states. Further validation is obtained by embedding the nanolayer in a larger-band-gap material: this removes the surface states and results in also the lowest conduction band showing quantum confinement [2].
[1] W. S. Hwang et al., Appl. Phys. Lett. 104, 203111 (2014).
[2] H. Peelaers and C.G. Van de Walle, Phys. Rev. B 96, 081409(R) (2017).
This lack of quantum confinement is due to the presence of a compensating effect: the interaction between surface states on both sides of the nanolayer. The lowest two conduction bands have surface character, and these states interact through the nanolayer, inducing a splitting that almost exactly compensates the quantum confinement. The midpoint between these bands does show the effect of quantum confinement, as do the higher conduction-band states. Further validation is obtained by embedding the nanolayer in a larger-band-gap material: this removes the surface states and results in also the lowest conduction band showing quantum confinement [2].
[1] W. S. Hwang et al., Appl. Phys. Lett. 104, 203111 (2014).
[2] H. Peelaers and C.G. Van de Walle, Phys. Rev. B 96, 081409(R) (2017).
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Presenters
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Hartwin Peelaers
Materials Department, University of California, Santa Barbara, University of California, Santa Barbara, Materials, Univ of California - Santa Barbara
Authors
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Hartwin Peelaers
Materials Department, University of California, Santa Barbara, University of California, Santa Barbara, Materials, Univ of California - Santa Barbara
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Chris Van de Walle
University of California, Santa Barbara, Materials Department, Univ of California - Santa Barbara, Materials Department, University of California, Santa Barbara, Materials, Univ of California - Santa Barbara, Materials Department, University of California - Santa Barbara, Materials Department, University of California