EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

We show that the control of the composition of CuCrO2 thin films allows the synthesis of highly conductive and transparent oxides by Aerosol Assisted CVD, a low-cost and non-vacuum deposition technique. The compositional, structural, and morphological properties were analyzed to understand the effect of the cationic ratio in the film, Cu/(Cu+Cr), on electrical and optical properties. The resistivity, the transparency, and the bandgap are reduced with the increase of Cu/(Cu+Cr) in the film. The electrical and optical properties were found optimal for Cu-rich CuCrO2 thin films with Cu/(Cu+Cr)=65%, resulting in a resistivity of 0.05 Ω.cm, and an average transmittance around 58%, culminating in a Gordon’s Figure of Merit (FoMg) of 2200 µS. Besides, a greater Cu incorporation leads to the synthesis of a composite film formed by Cu2O and CuCrO2. These films present an improved carrier mobility and reduced energy gap, with a resistivity around 0.02 Ω.cm, an average transmittance of 52%, resulting in a FoMg of 1400 µS.
These nanocomposite thin films were coupled with ZnO deposited by Spatial ALD in a planar p-n junction. This transparent diode was entirely synthesized by chemical deposition techniques at low temperature and atmospheric pressure, with no required post-deposition treatment. It shows an extremely high rectifying behavior, Ion/Ioff (±3V) around 10000, and a transmittance in the visible around 70%. The fitting of the diode characteristic led to values of 2.5, 3 Ω.cm2 and 5*105 Ω.cm2 for the ideality factor, series resistance, and shunt resistance, respectively. The combination of Cu-rich CuCrO2 and ZnO in a p-n junction here reported results in an all-oxide performing transparent diode revealing a great potential for transparent electronics.