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bilalarif
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I was reading about semiconductor transparent conducting oxides and I found this why p-type conductivity is limited in TCOs. But I could not understand its meaning please someone explain me how the holes are localized at valance band edge and how dominated by oxygen- 2p levels?
''Owing to the strong ionic nature of metal-oxygen bonding, holes are typically localized at the valence band
edge, which is dominated by oxygen-2p levels therefore limiting p-type conduction. Two methods have been
suggested to enhance the co-valency between metal oxygen bonding, thereby limiting localization:1 choosing cations having closed d-shells of energy comparable to that of the oxygen-2p levels (i.e., Cu+, Ag+, and Au+, especially when found in linear coordination with oxygen2), and choosing a structure in which oxygen adopts tetrahedral coordination''
''Owing to the strong ionic nature of metal-oxygen bonding, holes are typically localized at the valence band
edge, which is dominated by oxygen-2p levels therefore limiting p-type conduction. Two methods have been
suggested to enhance the co-valency between metal oxygen bonding, thereby limiting localization:1 choosing cations having closed d-shells of energy comparable to that of the oxygen-2p levels (i.e., Cu+, Ag+, and Au+, especially when found in linear coordination with oxygen2), and choosing a structure in which oxygen adopts tetrahedral coordination''