Effects of a zinc-blende–diamond order-disorder transition on the crystal, electronic, and vibrational structures of metastable (GaAs)1−x(

Epitaxial pulsed laser crystallization of amorphous germanium on GaAs

“…18 The presence of defects within the grains, however, may limit the phonon coherence length in a similar way as grain boundaries do, leading thus to a red-shift of the Raman line. The shape of the Raman spectrum is similar to those reported for Ge rich ͑GaAs͒ 1Ϫx Ge 2x alloys with x close to unity, [25][26][27] thus suggesting that the modifications in the Raman line are associated with the incorporation ͑and possibly doping͒ of Ga and/or As atoms from the substrate. The shape of the Raman spectrum is similar to those reported for Ge rich ͑GaAs͒ 1Ϫx Ge 2x alloys with x close to unity, [25][26][27] thus suggesting that the modifications in the Raman line are associated with the incorporation ͑and possibly doping͒ of Ga and/or As atoms from the substrate.…”

Nonisovalent Alloys for Photovoltaics Applications: Modelling IV-Doped III-V Alloys

“…In the case of ZnSe−GaAs, Wang et al report only small change in the final alloy bandgap, E G , as result of the introduction of larger bandgap II−VI dopants into the III−V host, while the opposite (GaAs in ZnSe) causes sharp drops in the bandgap of the alloy (Wang & Zunger, 2003). In recent years, many other papers have been focused on the class of (III-V) 1-x (IV 2 ) x nonisovalent alloys both at theoretical (Holloway, 2002;Newman et al, 1989;Osorio & Froyen, 1993;Ito & Ohno, 1992;Ito & Ohno, 1993;Newman & Jenkins, 1985;Bowen et al, 1983) and experimental (Green & Elthouky, 1981;Barnett et al, 1982;Alferov et al, 1982;Banerjee et al, 1985;Noreika & Francombe, 1974;Baker et al, 1993;Rodriguez et al, 2000;Rodriguez et al, 2001) level. The employment of nonequilibrium grown techniques that incorporate high dopant concentrations in semiconductors has boosted the attention towards this class of alloys.…”

“…In the ordered GaAs-rich phase, Ga and As preferentially form donoracceptor pairs, whereas in the Ge-rich phase, they are randomly distributed in the alloy forming a mixture of n-type and p-type semiconductors. The origin of the large bowing is ascribed to this ordered  disordered transition (Newman et al, 1989). Several other theoretical models have been developed in order to describe such zinc-blendto-diamond phase transition.…”

“…Several other theoretical models have been developed in order to describe such zinc-blendto-diamond phase transition. They are based on thermodynamic Newman et al, 1989;Gu et al, 1987;Koiller et al, 1985), percolation (D'yakonov & Raikh, 1982), and stochastic growth approaches (Rodriguez et al, 2000;A Rodriguez at al., 2001;Preger et al, 1988;Capaz et al, 1989). Owing to their intrinsic difficulty in taking into account possible different growth conditions, models based on the percolation method (D'yakonov & Raikh, 1982) predict a critical concentration for the transition at 0.57, quite far from the experimentally reported.…”

Impact of short‐range order and clusterization on the bandgap bowing: First‐principles calculations on the electronic properties of metastable (GaAs)1–x(Ge2)x alloys

“…This transition is usually associated with the mentioned asymmetry in the direct gap bowing. In order to reproduce such phase transition, several theoretical approaches for alloy configuration have been proposed: thermodynamic [18,19], percolation [20,21], and stochastic growth models [16,17,[22][23][24]. In stochastic growth models, the alloy configuration depends on the kinetics of the growth; Monte Carlo (MC) based models are here used to predict such configuration, being the atomic position of single layers dependent on the epitaxial growth direction.…”