Physics:Cu-Pt type ordering in III-V semiconductor

One of the most studied atomic ordering is CuPt type ordering in III-V semiconductor alloy. It occurs in III-V alloy when the cation planes take an alternate sequence of A-rich and B-rich plane following A_xB_1−xC. The resulting structure is usually called as superlattice-like structure along [1-11] or [-111] – called (111) B plane, or along [-1-1-1] or [11-1] – called (111) A plane. The two ordering direction is thus called CuPt type A and B ordering.

The same type ordering is also observed in II-VI alloy such as CdZnTe alloy. The ordering sequence viewed on atomic planes along [-111] and [1-11] reveals Cd and Zn alternating planes.

Example of Cu-Pt type ordering in Cd-Zn-Te alloy.

This ordering reduces the lattice symmetry ordering to L11 and leads to change of its optical and electrical properties. The apparent effects are: band gap reduction, valence band splitting, and optical anisotropy. For instance, in CuPt type B ordering, the L point of the Brillouin zone fold back to the Γ-point, and the folded band “repels” the original conduction band minimum and bring down the bottom of conduction band.

External links

• Jinghua, Zhao; Xiaohong, Tang; Jinghua, Teng (February 2009). "Atomic ordering of AlInP grown by MOVPE at different temperatures in pure ambient N₂". CrystEngComm 11 (6): 1068-1072. doi:10.1039/B817012F. https://doi.org/10.1039/B817012F. Retrieved 2021-05-02. 
• Kwon, Myoung Seok; Lee, Jeong Yong; Suh, Sang Hee (1998). "Observation of CuPt-Type Ordered Structure in CdZnTe during Organometallic Vapor Phase Epitaxial Growth". Japanese Journal of Applied Physics 37 (1A): L21. doi:10.1143/JJAP.37.L21. https://doi.org/10.1143/JJAP.37.L21. Retrieved 2021-05-02.