Origin of p-type conductivity in layered nGeTe center dot mSb(2)Te(3) chalcogenide semiconductors
2011 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, no 11, 113201- p.Article in journal (Refereed) Published
Ge2Sb2Te5, an extensively studied narrow-band-gap semiconductor for phase-change memories, always displays p-type conductivity. However, the defect physics and origin of the p-type conductivity are not yet clear. We have studied various types of defects in layered nGeTe center dot mSb(2)Te(3) (GST) using ab initio calculations. The results show that the formation energies of V-Ge are always the lowest followed by Sb-Te in the studied GST. The majority defects are V-Ge and Sb-Te, which results in the p-type conductivity of GST. Although Ge2Sb2Te5 always has a p-type character, one can make both p-and n-type GeSb2Te4 and GeSb4Te7 by tuning the atomic chemical environments.
Place, publisher, year, edition, pages
2011. Vol. 83, no 11, 113201- p.
IdentifiersURN: urn:nbn:se:uu:diva-151649DOI: 10.1103/PhysRevB.83.113201ISI: 000288646200002OAI: oai:DiVA.org:uu-151649DiVA: diva2:411024