Synthesis of nanocrystalline Cu deficient CuCrO₂ – a high figure of merit p-type transparent semiconductor

Abstract

The delafossite structured CuCrO 2 system is well known as one of the best performing p-type transparent conducting oxides. In this paper the details of a low temperature facile growth method for CuCrO 2 is described. The dependence of the growth on the precursors, the temperature and oxygen partial pressure are examined. The decomposition routes are critical to obtain the best performing films. The thermopower and electrical measurements indicate p-type films with conductivity ranging from 1-12 Scm −1 depending on the growth conditions. This p-type conductivity is retained despite the nanocrystallinity of the films. The figure of merit of these films can be as high as 350 µS, which is the best performing p-type TCO by solution methods to date. The optical properties are also investigated using ellipsometry and UV-Vis spectroscopy.

Transparent conductive CuCrO2thin films deposited by pulsed injection metal organic chemical vapor deposition: up-scalable process technology for an improved transparency/conductivity trade-off

“…It appears that the relative deficiency of copper in the films is mainly counter balanced by an excess of chromium in CuCrO 2 thin-films. The oxygen concentration close to the stoichiometric value of 50% is also a specific feature of our thin-films when compared to the optimized thin-films reported by Farrell et al 53 (Suggesting in their case an excess of oxygen for the optimum stoichiometry of Cu 0.4 CrO 2.5 .) Considering the chemical composition ( Fig.…”

“…We obtained a FOM of 2300 mS which is far higher than the best FOM recently reported (350 mS). 53 When plotting the average transmittance (in the visible wavelength range), and the conductivity at room temperature that are obtained for thin films of CuCrO 2 grown by various synthesis methods, we compare the transparency/conductivity of our p-type thin films with reported data in the literature (Fig. 9).…”

Transparent Electrodes for Efficient Optoelectronics

“…In related work cationic and anion substitution and the role of Cr vacancies in this material has been studied. [66,67] High conductivity has also been shown experimentally in non-Cu metal oxides, most notably spinel-structured TCOs, such as NiCo 2 O 4 , [68,69] perovskites-structured TCOs, such as SrIn x Ti 1-x O 3 and Sr x La 1-x CrO 3 , [70,71] and amorphous or composite oxides, such as ZnO·Rh 2 O 3 and In:MoO 3 . [72,73] Other oxides, such as doped Cr 2 O 3 and Ba 2 BiTaO 6 , have promise but remain to be synthesized with high conductivities.…”

X-ray spectroscopic studies of the electronic structure of chromium-basedp-type transparent conducting oxides

“…The defective material allows us, by altering the Cu/Cr ratio, to switch between two regions: a highly copper doped amorphous Cr 2 O 3 :Cu structure and a copper deficient CuCrO 2 . While less conductive than the crystalline CuCrO 2 :Mg, it has one of the highest FOMs, 350 μS, of any solution processed p-type TCOs [34].…”

“…1 Nanocrystalline, highly conductive, copper-deficient copper chromium oxide was grown by spray pyrolysis using a simple air blast nozzle. Copper(II) acetylacetonate and chromium(III) acetylacetonate precursors in a methanol solution were sprayed at 623 K on glass microscope slides [34]. The incorporated copper content of the Cu x CrO y films was controlled by altering the concentration of copper acetylacetonate in the initial precursor solution.…”