Predicting band offset of lattice matched ZnO and BeCdO heterojunction from first principles

Abstract

Using first-principles approach, we calculated the band gaps of wurtzite Be 1−x Cd x O ternary alloy and the band offset of the lattice matched ZnO/Be 0.44 Cd 0.56 O[1 1 2 0] heterojunction, where the modified Becke-Johnson semi-local exchange was used to determine the band gap and the coherent potential approximation was applied to deal with doping effect in disordered alloys. The ZnO/Be 0.44 Cd 0.56 O heterojunction was determined to have a type II band alignment, with valence and conduction band offset being 0.28 and 0.50 eV, respectively. The calculation approach and procedure demonstrated here can be used to predict the band offset of more lattice matched semiconductor heterojunctions. IMPACT STATEMENT The band offsets of lattice matched ZnO/Be 0.44 Cd 0.56 O heterojunction were predicted from first principles, where band gaps of semiconductors and configuration average of disorders were both accurately and efficiently calculated.

X-Ray Photoemission Investigation of the Beryllium Oxide Band Alignment with Magnesium Oxide and Estimates for Other Insulating and Conducting Oxides

“…Owing to a large bandgap (E g > 8 eV (1,2)), wurtzite crystal structure (3,4), and high solid solubility (5), beryllium oxide (BeO) has recently become of significant interest as an alloying agent with wide bandgap semiconductor zinc oxide (ZnO, E g = 3.3 eV) for bandgap engineering and charge carrier confinement in various oxide semiconductor based optoelectronic devices (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). BeO also exhibits many other excellent properties (1,(17)(18)(19)(20)(21) including a high dielectric constant (k = 6.7), high breakdown field (E bd > 6 MV/cm), high thermal conductivity (κ > 15 W/mK), and high hardness (H > 30 GPa) that makes it an excellent choice as an insulating gate dielectric (22,23), passivation layer (24,25), diffusion barrier (24), or epitaxial seed layer (27)(28)(29)(30) for both narrow (23,31) and wide bandgap semiconductor devices (32)(33)(34)(35)(36).…”