Open AccessAb initio calculation of band alignment of epitaxial La<sub>2</sub>O<sub>3</sub> on Si(111) substrate
Author(s) -
A. Debernardi
Publication year - 2015
Publication title -
aims materials science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.367
H-Index - 16
eISSN - 2372-0484
pISSN - 2372-0468
DOI - 10.3934/matersci.2015.3.279
Subject(s) - band offset , epitaxy , materials science , heterojunction , doping , band gap , dielectric , condensed matter physics , pseudopotential , optoelectronics , ab initio , chemistry , valence band , nanotechnology , physics , organic chemistry , layer (electronics)
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