![]() ![]() The ionic radius of M 3+ in Cu 1+ M 3+O 2 delafossite is 0.41, 0.535, 0.62, and 0.80 Å for M = B 3+, Al 3+, Ga 3+, and In 3+, respectively.Ĭu MO 2 delafossites (where M = Al, Ga, and In) have been reported to exhibit a wide optical direct gap and p-type behavior. Cu MO 2 delafossites, where M is a group 13 metal cation, consist of CuBO 2, CuAlO 2, CuGaO 2, and CuInO 2. MO 6 octahedra are formed by the sharing of − edges. 5 Cu + is linearly connected to two O 2−, resembling dumbbell shapes along the c axis. 4 The structure of Cu-based delafossite consists of alternating layers of Cu + and MO 6 octahedra, staked along the c axis. reported that CuAlO 2 delafossite exhibited p-type behavior with a direct energy gap of 3.5 eV. p-type TCO materials of Cu-based delafossite compounds have been recently investigated. ![]() TCO materials require optical direct energy gaps ( Eg) of >3.1 eV, 2,3 to ensure the protecting visible light excitation of electrons from the valence to conduction bands. In particular, p-type transparent materials are used in touch screens, mobile phones, and smart mobile devices. Transparent conducting oxides 1 (TCO) have applications as electrodes in advanced electronic devices. CuBO 2 delafossite is a p-type transparent conducting oxide with a wide band gap and may have potential in industrial p-type electrodes. Activation energies for carrier production and electrical conduction were 0.147 and 0.58 eV, respectively, indicating the thermal activation of carriers. Emission at 355 nm indicated a direct band type transition, and the UV-VIS-NIR spectrum indicated an optical direct gap of 3.6 eV. The positive Seebeck coefficient confirmed p-type behavior. TGA indicated a weight loss of 10%, which was attributed to excess oxygen. CuBO 2 delafossite possesses a hexagonal space group R 3 ¯ m. Its crystal structure, morphology, composition, oxygen decomposition, and optical and electronic properties were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis (TGA), ultraviolet-visible-near-infrared (UV-VIS-NIR) and fluorescence spectroscopies, Seebeck coefficient, and electrical conductivity measurements. The optical properties of this p-type transparent conducting oxide were investigated. CuBO 2 delafossite was prepared by solid state reaction and calcined/sintered at 1005 ☌. ![]()
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