Structural and electronic properties of ZnGeAs{sub 2}

Journal Article · Tue May 15 04:00:00 EDT 2001 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.63.195210· OSTI ID:40205507

Janotti, A; Wei, Su-Huai; Zhang, S B; Kurtz, Sarah

Using a first-principles band-structure method based on density functional theory, we have studied the structural and electronic properties of ZnGeAs{sub 2}. In agreement with experimental data, ZnGeAs{sub 2} is found to be nearly lattice matched to its binary analog GaAs. The calculated band structures show that ZnGeAs{sub 2} in the chalcopyrite structure has a direct band gap, about 0.31 eV smaller than the band gap of GaAs. The calculated valence-band offset between ZnGeAs{sub 2} and GaAs is 0.18 eV; thus, the band alignment of the ZnGeAs{sub 2}/GaAs system is type I, with both holes and electrons localized on ZnGeAs{sub 2}. We also find that at low temperature, (ZnGeAs{sub 2}){sub 0.5}(GaAs) forms a stable stannite structure. However, the band gap and the mixing energy of the alloy at higher temperature depend sensitively on the local short-range order. The calculated formation energies of the (ZnGeAs{sub 2}){sub n}(GaAs){sub 2n} superlattices along the [001] direction show strong nonmonotonic behavior, with the formation energy {Delta}H{sub n} maximized at n=2. We compared our results for the ZnGeAs{sub 2}/GaAs system to the well-studied CuGaSe{sub 2}/ZnSe system. The differences between these two systems are explained in terms of their ionicity and their relative strength of the anion p and cation d couplings.

• Sponsoring Organization: (US)
• OSTI ID: 40205507
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 19 Vol. 63; ISSN 0163-1829
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALIGNMENT
ALLOYS
ANIONS
CATIONS
CHALCOPYRITE
ELECTRONS
FUNCTIONALS
SUPERLATTICES