Chemical trends of stability and band alignment of lattice-matched II-VI/III-V semiconductor interfaces

Hui-Xiong Deng, Jun-Wei Luo, Su-Huai Wei
2015 Physical Review B  
Using first-principles density functional theory (DFT) method, we systematically investigate the structural and electronic properties of heterovalent interfaces of the lattice-matched II-VI/III-V semiconductors, i.e. ZnTe/GaSb, ZnSe/GaAs, ZnS/GaP and ZnO/GaN. We find that independent of the orientations, the heterovalent superlattices with period n = 6 are energetically more favorable to form nonpolar interfaces. For the [001] interface, the stable nonpolar interfaces are formed by mixing 50%
more » ... med by mixing 50% group III with 50% group II atoms or by mixing 50% group V with 50% group VI atoms; For the [111] nonpolar interfaces, the mixing are 25% group III (II) and 75% group II (III) atoms or 25% group V (VI) and 75% group VI (V) atoms. For all the nonpolar interfaces, the [110] interface has the lowest interfacial energy because it has the minimum number of II-V or III-VI "wrong bonds" per unit interfacial area. The interfacial energy increases when the atomic number of the elements decreases, except for the ZnO/GaN system. The band alignment between the II-VI and III-V compounds are drastically different whether they have a mixed-cation or mixed-anion interfaces, but the averaged values are nearly independent of the orientations. Similarly, other than ZnO/GaN, the valence band offsets also increase as the atomic number of the elements decreases. The abnormal trends in interfacial energy and band alignment for ZnO/GaN are primarily attributed to the very short bond lengths in this system. The underlying physics behind these trends are explained.
doi:10.1103/physrevb.91.075315 fatcat:7vyabatmgvbczc5fmtfkpxmgf4