The nano-copper oxide film has good transparent conductivity, piezoelectricity, photoelectricity, gas sensitivity, pressure sensitivity, and is easy to integrate with a variety of semiconductor materials. Due to these excellent properties, it has a wide range of applications and many potential applications, such as optoelectronic devices, surface acoustic wave devices, planar optical waveguides, transparent electrodes, transparent conductive films, piezoelectric devices, gas sensors, and buffer layers of GaN Wait.
(1) Application of nano-copper oxide film in optoelectronic device
The direct band gap (3.37 eV) and high exciton binding energy (60meV) of nano-copper oxide make it theoretically possible to obtain efficient UV exciton emission and laser at room temperature. At the same time, through the alloy thin film composed of CdO and MgO, an adjustable band gap (2.8-4.2eV) can be obtained, covering the spectral range from red to ultraviolet light. It is expected to develop a variety of light emitting devices such as ultraviolet, green, and blue . In particular, the preparation of p-CuO opens the way for the application of nano-copper oxide in the fields of ultraviolet detectors, LEDs, and LDs. At present, ZnO optoelectronic devices have been reported to include ultraviolet detectors and light emitting diodes.
(2) Application of nano-copper oxide film in surface acoustic wave device
Nano-copper oxide thin film has excellent piezoelectric properties, good high-frequency characteristics, high electromechanical coupling number and low dielectric constant. It is an ideal material for surface acoustic wave (SAW). The increase of mobile communication information transmission requires SAW exceeding 1 GHz. Therefore, the nano-copper oxide piezoelectric thin film has a very broad development prospect in the fields of high-frequency filtering, resonators, and optical waveguides. SAW requires nano-copper oxide thin film to have a c-axis preferred orientation and high resistivity, so as to have high acoustic-electric conversion efficiency; and requires fine grains, flat surface, and few crystal defects to reduce the scattering of SAW and reduce losses.
(3) Application of nano copper oxide film in solar cell
Nano-copper oxide films, especially AlO (CuO: Al) films, have excellent transparent conductive properties. Murata, Japan, has produced low-loss RF SAW filters of 1.5 GHz on sapphire substrates with epitaxial nano-copper films. Device, currently researching and developing 2GHz products. The transmittance in the light wavelength range can reach more than 90%, which can be compared with ITO (In2O3: SnO2) film. Compared with ITO film, AlO film is non-toxic, non-polluting, rich in raw materials, cheap, and highly stable (especially in hydrogen plasma). It is gradually becoming an alternative material for ITO films, and has been used in displays and solar energy. application. At present, the nano-copper oxide film is mainly used as a transparent electrode and window material for solar cells, and the nano-copper oxide film is less damaged by radiation from high-energy particles, so it is particularly suitable for use in space. Croenen et al. Used diffusion thermal plasma beam technology to prepare nano-copper oxide: Al thin films (ρ <10-3Ωcm, T> 80%), which are used for amorphous amorphous silicon solar cells with an efficiency of 7.7%. Nano-copper oxide treated with hydrogen plasma: Ga film can be used as a window material for solar cells, and its efficiency can reach 13%.
(4) Application of nano copper oxide film in gas sensing element
Nano-copper oxide-based thin film materials have good gas-sensitivity characteristics. When the film is exposed to gases of different compositions and concentrations, its resistivity will change accordingly. In general, when a reducing gas is adsorbed on the film surface, the resistivity of the film will decrease due to the reduction reaction, and the higher the gas concentration, the lower the resistivity. On the contrary, when an oxidizing gas is adsorbed on the film surface, the oxidation resistance Effect, the film resistivity will increase as the gas concentration increases. Based on this characteristic, various gas-sensitive sensors can be manufactured. Nano-copper oxide is a typical surface-controlling gas-sensitive material. Generally, the smaller the particle size, the larger the specific surface area, the larger the oxygen adsorption amount, and the higher the gas sensitivity of the material. In addition, the precious metal is doped with or coated with precious metal. Catalytic coating can increase its sensitivity and selectivity. The nano-copper oxide film prepared by Min et al. Has good sensitivity to H2, NO2, and CO, and has a particularly high sensitivity to NO2 at low temperatures; the Al-doped nano-copper oxide film can be at 400 ° C. Working at temperatures of up to 61.6% for CO.