Electrical properties of PbTe doped with BaF{sub 2}

• Published in: Journal of applied physics 2009-02, Vol.105 (4)
• Main Authors: Mengui, U. A., Abramof, E., Rappl, P. H. O., Diaz, B., Closs, H., Senna, J. R., Ueta, A. Y.
• Format: Article
• Language: English
• Subjects: BARIUM FLUORIDES; CARRIER DENSITY; CARRIER MOBILITY; CRYSTAL GROWTH; DOPED MATERIALS; ELECTRICAL PROPERTIES; HALL EFFECT; IMPURITIES; LEAD TELLURIDES; MATERIALS SCIENCE; MOLECULAR BEAM EPITAXY; PHONONS; SCATTERING; SEMICONDUCTOR MATERIALS; SUBSTRATES
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3082043

We study here the p-type doping of PbTe with BaF{sub 2}. For the investigation, PbTe layers were grown on (111) BaF{sub 2} substrates by molecular beam epitaxy. The beam flux ratio between BaF{sub 2} and PbTe, defined as the nominal doping level, was varied from 0.02% to 1%. The hole density increases from 5x10{sup 17} to 1x10{sup 19} cm{sup -3} as the doping level rises from 0.02% to 0.4% and saturates at p{approx}10{sup 19} cm{sup -3} for higher levels. The saturation effect was attributed to self-compensation. The carrier concentration of all samples remained almost constant as the temperature was varied from 10 to 350 K, indicating that no thermal activation is present in the whole doping range. It suggests that the impurity level in PbTe doped with BaF{sub 2} remains resonant with the valence band, similar to the native defects behavior. The low-temperature mobility showed a pronounced reduction from 50 000 to 2 000 cm{sup 2}/V s as the doping level rises from 0.02% to 1%, mainly due to the substantial increase in the hole concentration. For temperatures higher than 80 K, the mobility was essentially limited by phonon scattering. Our results demonstrate that a controlled p-type doping of PbTe with BaF{sub 2} can be obtained up to 10{sup 19} cm{sup -3}.