Studies Of The Growth Of NiO Materials And The Fabrication Of NiO-based Photoelectric Devices

NiO is a direct wide bandgap semiconductor materials, and the band gap is between3.6~4.0eV at room temperature. The common structure is cubic NaCl-structure and it is a typicalexample of transition metal oxide having a3d electron structure. The unique electronicstructure and characteristics of p-type conductivity made NiO have many unique properties andshow its broad application prospects, especially in the field of transparent conductive, gassensing, UV detection and electrochromic.The major work of this thesis is focusing on preparing NiO film material through twokinds of processes and studying the electrical and optical properties of the devices thatfabricated by the prepared NiO film material.NiO thin films are grown by MOCVD and magnetron sputtering techniques, respectively.In the experiment of NiO films grown by MOCVD, the effects of the growth temperature andsource gas flow ratios on the properties of the films’ surface morphology, crystal quality, opticalproperties and electrical characteristics are analyzed and the range of optimized growthconditions are obtained. In addition, in the experiment of NiO films grown by magnetronsputtering, the effects of the growth temperature, O2/Ar gas flow ratios and sputtering power onthe properties of the films’ surface morphology, crystal quality, optical properties and electricalcharacteristics are also analyzed and the range of optimized growth conditions are obtained aswell.We have studied the application of the NiO film material in the photoelectric device andfabricated two types of devices, one of them included n-ZnO/i-NiO/n-GaN, n-ZnO/i-NiO/p-GaN and n-ZnO/i-NiO/p-Si heterojunction devices with NiO grown byMOCVD method, the other consisted of n-ZnO/p-NiO/p-Si, p-NiO/n-GaN and p-NiO/GaNheterojunction devices with NiO grown by magnetron sputtering method. The fabricationmethods and characteristics of the device were introduced and studied in detail. By the way,several methods to fabricated excellent performance optoelectronic devices based on the NiOfilm material were obtained.n-ZnO/i-NiO/n-GaN, n-ZnO/NiO/p-GaN and n-ZnO/i-NiO/p-Si heterojunction diodeswith NiO as the electron blocking layer were fabricated by MOCVD technology.The deviceexhibited desirable rectifying behaviour. Ultraviolet light electroluminescence was observedfrom NiO heterojunction device under forward bias at room temperature. Such resultssuggested NiO played an important role in these UV-LEDs. Thus NiO as the electron blockinglayer would become possible ways to prepare efficient UV-LEDs.p-NiO/n-GaN and n-ZnO/p-NiO/p-Si heterojunction diodes with p-NiO were fabricated bymagnetron sputtering technology. The device also exhibited desirable rectifying behaviour.Ultraviolet light electroluminescence was observed from the device under forward bias at roomtemperature as well. Such results suggested p-NiO played an important role in these UV-LEDsand NiO would become possible candidate materials to prepare efficient UV-LEDs.