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arXiv · 1407.2342

Effects of the Cu off-stoichiometry on transport properties of wide gap p-type semiconductor, layered oxysulfide LaCuSO

Yosuke Goto·Mai Tanaki·Yuki Okusa·Taizo Shibuya·Kenji Yasuoka·Masanori Matoba·Yoichi Kamihara
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Abstract

Layered oxysulfide LaCuSO (x = 0-0.03) was prepared to elucidate the effect of Cu off-stoichiometry on their electrical and thermal transport properties. Electrical resistivity drastically decreases down from ~10^5 ohmcm to ~10^-1 ohmcm as a result of Cu deficiency (x = 0.01) at 300 K. Thermal conductivity of the samples at 300 K, which is dominated by lattice components, is estimated to be 2.3(3) Wm^-1K^-1. Stoichiometric LaCuSO has an optical band gap of 3.1 eV, while broad optical absorption at photon energies of approximately 2.1 eV was observed for Cu-deficient samples. Density functional theory calculation suggests that these broad absorption structures probably originate from the in-gap states generated by the sulfur vacancies created to compensate the charge imbalance due to Cu off-stoichiometry. These results clearly demonstrate that Cu deficiency plays a crucial role in determining the electrical transport properties of Cu-based p-type transparent semiconductors.

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Yosuke Goto, Mai Tanaki, Yuki Okusa, Taizo Shibuya, Kenji Yasuoka, Masanori Matoba, Yoichi Kamihara. 2014-07-24. Effects of the Cu off-stoichiometry on transport properties of wide gap p-type semiconductor, layered oxysulfide LaCuSO. https://doi.org/10.1063/1.4890302

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