P-type Semiconductor Oxides Micro/Nano-structure And Fabrication Of Photoelectric Devices

Semiconductor oxides have drawn great attention due to its potential applications in optoelectronic devices, including light emission diodes, laser diodes, and photodetectors. Because the acquiring of stable and reproducible p-type inorganic semiconductors is still a great challenge, the reports based on the p-n homojunction optoelectronic devices have been extremely limited until now. To obtain high performance semiconductor detectors, the p-n junction is an ideal device structure, since p-n junction photodetectors usually have advantages of high sensitivity, fast responding speed, low dark currents, and high stability in the atmosphere. In this work, we try our effort to obtain high quality p-type semiconductors by means of p-type doping of excellent semiconductor such as ZnO and exploring intrinsic p-type semiconductors such as CuGaO₂. Our main works are listed as follows:1. The ultralong Sb-doped p-type Zn O single crystalline microwires with an average length of 10 millimeters were synthesized via a chemical vapor deposition method. A p-n homojunction UV photodetector was fabricated by crossing a single Sb-doped and a single undoped ZnO microwire together. The fine rectification characteristics were obtained on the p-n homojunction.2. The UV photodetector exhibited perfect wavelength selectivity with a full width at half maximum（FWHM） of only 6 nm. The peak responsivity of this UV photodetector is 200 mA/W with the response peak of 386 nm under-5 V biases, the photodetector showed the external quantum efficiency（EQE） of about 64.5%.3. CuGaO₂ nanoplates obtained through a simple hydrothermal method showed high crystalline and p-type properties. p-type properties of CuGaO₂ nanoplates were examined by photoluminescence and electrical measurements. The CuGaO₂ nanoplates exhibited strong blue emission at room temperature. The blue emission resulted from Cu vacancy defect which is the possible source of p-type conductivity.4. A device composed of CuGaO₂ nanoplates and ZnO film was constructed in order to test the electrical properties of p-CuGaO₂/n-Zn O heterostructure,the device structure is Au/p-CuGaO₂/n-ZnO/ITO,it shows good rectifying behavior with a turn-on voltage of about 4 V. The result indicates that the CuGaO₂ nanoplates have the characteristics of p-type conduction, and its combination with ZnO could form a typical p-n junction. A simple calcination reaction method was used to fabricate p-type CuGaO₂/n-type ZnO nanocomposite heterostructures which have perfect applications in photocatalysis. The as-obtained products exhibited enhanced photodegradation efficiency with respect to the individual constituents. The enhancement is attributed to the restraining recombination of photo-induced carries and the enhanced visible light absorption resulted from the formation of p-n junction.