Preparation And Optoelectronic Performance Study Of Copper-Based Compound Materials And Devices

In recent years,emerging third-generation semiconductor materials such as gallium oxide and zinc oxide have become key components in various electronic devices and high-frequency components due to their outstanding performance,including high efficiency,low temperature,low voltage,low power consumption,and good radiation resistance.They have been widely applied in fields such as lighting,communication,and energy.While gallium nitride has achieved some success in p-type doping,materials like zinc oxide and gallium oxide exhibit intrinsic n-type conductivity due to the presence of oxygen vacancies.It is extremely difficult to achieve p-type doping in these semiconductor materials,which severely hampers the application of homojunctions and heterojunction devices in the aforementioned fields.Furthermore,the absence of p-type semiconductor materials limits the further development of pn junction devices.Copper-based compound semiconductor materials,represented by cuprous iodide（CuI）and cuprous bromide（CuBr）,exhibit inherent p-type conductivity due to the presence of copper vacancies.They also have a wide bandgap of Eg≥3.0 e V,weak internal electric fields,and high bond energies,making them promising for short-wavelength optoelectronic devices with high photovoltaic conversion efficiency and chemical stability.The key to commercializing copper-based compound semiconductor materials such as CuI and CuBr lies in improving their film quality.However,CuI and CuBr materials still face challenges such as poor film quality in epitaxial thin films and high defect density.This article investigates the high-quality growth of copper-based compound semiconductor thin films,such as CuI and CuBr,using vacuum thermal evaporation technology.By designing and fabricating different heterojunction devices,the optoelectronic properties of the devices are studied,providing theoretical and experimental support for the preparation and optoelectronic device applications of copper-based compound semiconductor materials.The main work of this article includes the following:1.Preparation of high-quality CuI thin films and study of the optoelectronic properties of CuI/Ga N heterojunction devices.This work investigates the growth of CuI on epitaxial Ga N thin film substrates and constructs CuI/Ga N heterojunction self-driven ultraviolet photodetectors.A layer of CuI thin film is grown on Ga N and quartz substrates using vacuum thermal evaporation technology,and the characterization results show that CuI exhibits high growth orientation on both quartz and Ga N substrates,with only（111）orientation growth.CuI/Ga N heterojunction detectors are fabricated,and the optical properties of CuI thin films and the photodetection characteristics of the devices are studied.The results show that the CuI/Ga N heterojunction exhibits good self-driven and rectifying characteristics,with the highest sensitivity to 360 nm light.At 0 V bias and under 360 nm（～0.32 m W/cm²）illumination,the on/off ratio is approximately 2320,and the peak responsivity and detectivity are 75.5 m A/W and 1.27×10¹² Jones,respectively.The detector also demonstrates good self-driven time response stability.2.Preparation of CuI Nanomaterials and Study on the Photoelectric Properties of CuI/Ti O₂ Heterojunction Photodetectors.To achieve a larger contact area,the growth of CuI on a one-dimensional Ti O₂ nanorod array substrate was investigated.A self-powered CuI/Ti O₂ nanorod heterojunction photodetector was constructed,and the photoelectric characteristics of the device were studied.Firstly,one-dimensional Ti O₂nanorod arrays were grown on substrates with different growth times using a hydrothermal method,and the influence of different growth times on the substrate was investigated and characterized.Based on this,a CuI/Ti O₂ heterojunction device was constructed by depositing a layer of CuI using vacuum thermal evaporation technology on a one-dimensional Ti O₂ nanorod array grown for 6 hours,and the photoresponse characteristics of the device were systematically studied.The results showed that the prepared heterojunction device exhibited good rectification characteristics and self-powered behavior.Under 0 V bias,the spectral responsivity and detectivity peak of the device were both located at 410 nm,with peak responsivity and detectivity values of 4.5 m A/W and 1.08×10¹¹ Jones,respectively.The photocurrent and dark current at 0 V were 3.15×10^-7 A and 4.10×10^-10 A,respectively,and the on/off ratio was～770.3.Preparation of CuBr Polycrystalline Films by Vacuum Thermal Evaporation and Study on the Performance of CuBr/Ga N Heterojunction Photodetectors.CuBr films were deposited on quartz and Ga N substrates using vacuum thermal evaporation,and a CuBr/Ga N heterojunction self-powered ultraviolet photodetector was constructed.By growing CuBr films as hole transport layers,the optical properties of CuBr and its applications in the detection field were systematically studied.The heterojunction device exhibited dual-band detection characteristics at 360 nm and 420 nm.Under 0V bias and 360 nm illumination,the responsivity,detectivity,and on/off ratio reached6.59 m A/W,4.9×10¹¹ Jones,and 4294,respectively.Under 0V bias and 420 nm illumination,the values were 0.79 m A/W,5.9×10¹⁰ Jones,and 268.11,respectively.Furthermore,after being exposed to the atmospheric environment for 100 days,the emission peak position of the film and the device did not exhibit any redshift or blueshift.Under 0 V bias,the detector could still maintain 96%and 90%of its original photoelectric current under 360 nm and 420 nm illumination,respectively.