First-principles study of defect properties of zinc blende MgTe

Abstract

We studied the general chemical trends of defect formation in MgTe using first-principles band structure methods. The formation energies and transition energy levels of intrinsic defects and extrinsic impurities and some defect complexes in zinc-blende MgTe were calculated systematically using a new hybrid scheme. The limiting factors for p-type and n-type doping in MgTe were investigated. Possible solutions to overcome the doping limitation of MgTe are proposed. The best p-type dopant is suggested to be N with nonequilibrium growth process and the best n-type dopant is suggested to be I with its doping complex VMg+4IT e.

Structural and optoelectronic properties of Mg substituted ZTe (Z=Zn, Cd and Hg)

“…The lattice constants of other three binary semiconductors CdTe, HgTe and MgTe are slightly overestimated than the experimental results but are in reasonably good agreement as compared to the calculated values by LDA [25,40] and GGA-PBE [24,37]. The overestimation can be related to the general trend of GGA as is clear from the reported results for ZnTe [24,35], CdTe [35], HgTe [37] and MgTe [24].…”

“…The results for Mg x Zn 1-x Te are also compared in the table with the other theoretical results [24]. [25,40] values are overestimated and the results of GGA [24] are underestimated in comparison with the experimental results. The table also presents comparison of our calculated values for the bulk moduli for the ternary compounds with the theoretical results of Charifi et al [24].…”

Enhanced p-type dopability of P and As in CdTe using non-equilibrium thermal processing

“…The AX center is stabilized when the electronic energy gain is larger than the energy expended in breaking two anion-cation bonds. 44 Differing from the local density approximation (LDA) results in Ref. 40, our HSE06 calculations show that both P Te and As Te can form AX centers when they have þ1 charged state with the stability energies [defined as DEðAXÞ ¼ EðAX; þ1Þ À EðP Te ; þ1)] of 0.50 and 0.52 eV, respectively.…”

Transparency and p-Type Conductivity of BeSe Doped with Group VA Atoms: A Hybrid Functional Study

“…In this work, the instinct defects, including Be vacancies (V Be ), Se vacancies (V Se ), Be antisites (Be Se ), Se antisites (Se Be ), Be interstitials (Be i ), and Se interstitials (Se i ) are considered. Owing to large perturbations, it is difficult to decide whether an intrinsic defect is an acceptor or a donor. , Whether a defect is an acceptor or a donor depends on the positions of the impurity states, which are decided by the potential difference between dopants and host elements.…”

“…The t v2 states for V Se are above CBM; therefore, V Se is a donor. 59,60 If a low-valence atom is replaced by a high-valence atom (e.g., Se Be ) or a dopant goes to an interstitial site (e.g., Be i and Se i ), the defect states a 1v and t 2v often remain inside the valence band, while both a c1 and t 2c states, created from the host conduction band states, move downward in energy. 59,60 These states are occupied by the nominal valence electrons of the defects plus the valence electrons associated with its neighboring atoms.…”