Ab initio calculation of band alignment of epitaxial La<sub>2</sub>O<sub>3</sub> on Si(111) substrate

Alberto Debernardi; Alberto Debernardi

doi:10.3934/matersci.2015.3.279

AIMS Materials Science

2015, Volume 2, Issue 3: 279-293. doi: 10.3934/matersci.2015.3.279

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Ab initio calculation of band alignment of epitaxial La₂O₃ on Si(111) substrate

Alberto Debernardi ^,

CNR-IMM, ss Agrate Brianza, via C. Olivetti 2, I-20864, Agrate Brianza, Italy, European Union

Received: 20 May 2015 Accepted: 17 August 2015 Published: 31 August 2015

By means of plane wave pseudopotential method we have studied the electronic properties of the heterostructure formed by an high dielectric constant (k) oxide, the hexagonal La₂O₃ epitaxially grown with (0001)-orientation on Si (111) substrate. We found that for La₂O₃ both the dielectric constant along the growth direction and the band gap are larger in the epitaxial film than in the bulk. By super-cell techniques we have computed the band alignment of the junction finding a valence band offset and a conduction band offset of ~1.6 eV and ~1.7 eV respectively. We demonstrate that the band alignment can be engineered by δ-doping the interface: our simulations show that, by doping the interface with S or Se monolayer, the valence (conduction) band offset increases (decreases) of about 0.5 eV without the formation of spurious electronic states in the semiconductor band-gap. The simulation of the critical thickness of pseudomorphic Lanthana film complete the work. Our results are relevant for the realization of a new generation of devices based on ultra-scaled complementary metal oxides semiconductors (CMOS) technology.
- High-k Oxides,
- Lanthana,
- Band-engineering,
- ultra-scaled CMOS,
- ab initio simulation
Citation: Alberto Debernardi. Ab initio calculation of band alignment of epitaxial La2O3 on Si(111) substrate[J]. AIMS Materials Science, 2015, 2(3): 279-293. doi: 10.3934/matersci.2015.3.279

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Abstract

By means of plane wave pseudopotential method we have studied the electronic properties of the heterostructure formed by an high dielectric constant (k) oxide, the hexagonal La₂O₃ epitaxially grown with (0001)-orientation on Si (111) substrate. We found that for La₂O₃ both the dielectric constant along the growth direction and the band gap are larger in the epitaxial film than in the bulk. By super-cell techniques we have computed the band alignment of the junction finding a valence band offset and a conduction band offset of ~1.6 eV and ~1.7 eV respectively. We demonstrate that the band alignment can be engineered by δ-doping the interface: our simulations show that, by doping the interface with S or Se monolayer, the valence (conduction) band offset increases (decreases) of about 0.5 eV without the formation of spurious electronic states in the semiconductor band-gap. The simulation of the critical thickness of pseudomorphic Lanthana film complete the work. Our results are relevant for the realization of a new generation of devices based on ultra-scaled complementary metal oxides semiconductors (CMOS) technology.

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