Lead monoxide α-PbO: electronic properties and point defect formation

• Published in: Journal of physics. Condensed matter Vol. 25; no. 7; p. 075803
• Main Authors: Berashevich, J, Semeniuk, O, Rubel, O, Rowlands, J A, Reznik, A
• Format: Journal Article
• Language: English
• Published: England 20-02-2013
• Subjects: Computer Simulation; Electric Conductivity; Electron Transport; Lead - chemistry; Models, Chemical; Models, Molecular; Oxides - chemistry
• ISSN: 1361-648X
• DOI: 10.1088/0953-8984/25/7/075803

The electronic properties of polycrystalline lead oxide consisting of a network of single-crystalline α-PbO platelets and the formation of native point defects in the α-PbO crystal lattice are studied using first-principles calculations. The results suggest that the polycrystalline nature of α-PbO causes the formation of lattice defects (i.e., oxygen and lead vacancies) in such a high concentration that defect related conductivity becomes the dominant mechanism of charge transport. The neutral O vacancy forms a defect state at 1.03 eV above the valence band which can act as a deep trap for electrons, while the Pb vacancy forms a shallow trap for holes located just 0.1 eV above the valence band. The ionization of O vacancies can account for the experimentally found dark current decay in ITO/PbO/Au structures.