27 September 2008 Nature of group-III related deep centers in lead telluride based semiconductors: Ga doping from vapor phase
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Doped with Ga lead telluride was taken as a model object to explain the nature of group-III deep levels in IV-VI semiconductors and to elucidate the vapour phase doping mechanism. For this goal interaction of various gallium-containing molecules with defect-free crystal as well as with native defects in PbTe were considered. The first-principle density functional theory calculations using 216-atoms supercell were performed. Formation energies for different point defects created in PbTe as a result of interaction the Ga2Te molecules, Ga2 dimers and single Ga atoms with a host crystal were calculated. Particularly GaPb and Gai together with formation of accompanied Pbi and Tei self interstitials in various charge states were examined. In addition we propose the new type of defects - the impurity complex (Ga2)Pb which looks like < 111 >-oriented gallium dumbbell. Calculations suggest the double donor behavior and DX-like properties of this defect together with extremely low formation energy values. Namely, GaPb centers are preferably formed under Ga2Te doping while (Ga2)Pb + Pbi ones are formed under Ga2 or Ga doping. In all cases formation energies are negative and resulting defect concentration is determined by the reaction kinetic only. Mechanisms of the lead vacansy compensation with the vapour phase doping is considered as well.
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Taras L. Petrenko, Sergey V. Plyatsko, Fiodor Fedorovych Sizov, "Nature of group-III related deep centers in lead telluride based semiconductors: Ga doping from vapor phase", Proc. SPIE 7100, Optical Design and Engineering III, 71002O (27 September 2008); doi: 10.1117/12.798361; https://doi.org/10.1117/12.798361


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