The Electrical Properties Of ZnO Thin Films

Recently much attention has been paid to short wavelength lasers for use in highdensity information storage, information display, UV communication, medicaltreament & diagnisis, and so on, which make it become an important basal researchwith extensive application. It is widely accepted that ZnO is one of the mostpromising materials for producing an ultraviolet laser at room temperature due to itswide direct band gap (Eg=3.3eV) and large excitonic binding energy of 60 meV,which was testified by the results of optically pumped stimulated emission and lasingfrom ZnO thin films. Like GaN compound, the reasearch about ZnO has burned whitehot in the range of wide band gap. Japanese scientists, Chinese scientists andAmerican scientists have fabricated LED based on ZnO film, however, developmentof LD has been limited by the lack of the higher qulity n-type and reliable p-typeZnO.. According to the present research hotspots and difficulties on ZnO, weinverstigated the electric properties of ZnO thin films. The details are as follow:1. Investigated undoped ZnO thin films which were prepared by P-MBE .Found thatthe ZnO thin films posses the best electric properties prepared at 650℃ by halleffect. . N-doped Zinc oxide Metal condution behavior emerged, when ZnOthin films have grown on c-Al2O3 substrate in Zn-rich conduction andlow substrate temperature.2. The reasons for unstable p-type ZnO were discussed. The p-type ZnO thin filmconverts to n-type after illumination by blue light of photon energy over than 2.67eV. Considering the effect of nonequilibrium n-type conduction in p-type ZnO, adeeper level trap states model was supposed.3. Prepared Au, In and Ni/Au contacts on p-type ZnO thin films. Compared differentannealing conditions, found Ni/Au contact gives a better ohmic characteristic...