Fabrication Of P Type ZnO Films And Research On Its Properties

ZnO is a versatile II-VI group semiconduct material with wide band-gap, due to its notable piezoelectric and photoelectric property. ZnO has been used in solar cells, surface acoustic wave devices, piezoelectric and gas sensing devices. Besides, ZnO is more resistant to radiation damage and has high exciton binding energy which enable ZnO has stronger emissing intensity under ultraviolet stimulated (In fact, this was confirmed by experiment). The excellent properties of ZnO indicate that it can be made into UV detectors, blue light emitting diodes, short wave lasers which are attractive to people.Since the first report of ZnO emiting under ultraviolet stimulated at room temperature in 1996, ZnO has attracted much attention act as a novel wide band gap semiconduct material.The research of ZnO has involved the synthesis of crystalline ZnO, nano-ZnO, quanta dot, quanta wires, research on their properties and its p type doping, research on ZnO has made great progress in a few years. However, on the international scholarship meeting about ZnO that hold in the United States on October 2002, scholars came from all the world made an aggrement that there was no way to reproduce grow p type ZnO with good electronic and stabilization properties. On September 2006, Q.Wan in Applied Physics Letters also said it is a huge challenge to prepare p type ZnO with low resistivity and high mobility. It is clearly that it remains the most pivotal topic to prepare p type ZnO and it is a stubborn but pivotal problem which must be solved to make ZnO based devices.In this thesis, c-axis preferential orientation p type ZnO films were prepared through optimizing deposition conditions by the improved USP system. The electronic and structure properties of as-grown ZnO films were analyzed by employing Hall, XRD, SEM, SIMS, XPS measurements. Here, firstly focused on the design and improvement of the USP system. Effect of the solution concentration, doping, substrate temperature, deposition time and substrate types on the properties of ZnO films was also paid attention. The detailed results in the following:1. A simple and practical nozzle has been designed. The reliability of experiment and crystalline of ZnO films are largerly improved.2. ZnO films deposited under 440℃have the best electronic, structure properties and good transmittance. On this temperature, we have obtained p type ZnO films with good properties on common glass and corning7059 glass substrates,the atomic ratio of Zn, N and Al are 1:3:0.10 and 1:3:0.07 respectively, and the corresponding electronic parameters are as follows:On cmmon glass:resistivity is 8.1??cm, hall mobility is 4.3cm2?V-1?s-1 and carrier concentration is 1.8×1017cm-3;On corning 7059 glass: resistivity is 3.58??cm, hall mobility is 2.17 cm2?V-1?s-1 and carrier concentration is 8.01×1017cm-3;3. If substrate temperature is appropriate, solution concentration almost have no effect on the electronic properties of ZnO films in this experiment;4. There is great difference in electronic properties of films deposited on different substrates. Thereinto, contrary conduction type of ZnO films grown on common glass and 7059 glass substrates under the same conditions is result from Na ion in common glass substrate diffused into ZnO films; besides, electronic properties of films deposited on low resistivity silicon substrate have several orders better than these deposited on common glass substrate, which is result from the effect of silicon substrate on Hall measurement.5. The results of PL measurement indicated that ZnO films have better luminescence properties when the substrate temperature, Zn:N:Al atomic ratio are 440℃and 1:3:0.1.