Reseach On Preraration Of ZnO Thin Film And Its Heterojunctions

The semiconductor Zn O has gained substantial interest in the research community in part because of its large exciton binding energy which could lead to lasing action based on exciton recombination even above room temperature. Zn O has gained substantial interest in the research community in part because of is large ecciton binding energy which could lead to lasing action based on reccombination even above room temperature. Prof. Zhong Lin Wang introduced a new type electronic components and optoelectronic device which used piezopotential to control the internal charge transfer process of the device, created the piezotronics and piezo-phototronics, make the Zn O and other piezoelectric semiconductor materials having more innovative design ideas and a wider range of applications.In this paper, we used the pulsed laser deposition technology for the preparation of Zn O thin films and study the characteristics of Zn O thin film growth Condition; Prepared Zn O heterojunction devices, measured their I-V characteristic curve and studied the output of the device under 365 nm ultraviolet light illuminate.Alse analysised the influence of piezopotential to the internal charge transfer process in the device, detailed work is as following:1. Fabrication of Zn O thin films by pulsed laser deposition, respectively choose single crystal Si, single crystal STO as the substrate, studied the crystal structure and photoluminescence spectrum of the Zn O thin film at different substrate temperature, found under 600 ℃, the Zn O thin film has the best crystal structure and a better intrinsic luminescence; Used single crystal STO substrate as the substrate, the influence of the oxygen partial pressure on Zn O thin film growth was studied, found hypoxia has great adverse impact to the intrinsic luminescence of Zn O thin films;2. ZnO thin films was deposited on p-Si substrate by PLD, and the n-ZnO/SiOx/p-Si heterojunction devices was preparated. Through the I-V test of the device,we found that the ratio of forward curret and reverse current,IF/IR ≈104.Under 2 V bias voltage and 365 nm UV-light, responsivity of the devices is 0.19 A/W, the response time to UV-light : Ton = 200 ms and Toff = 350 ms.3. Used the stripped mica sheet for flexible transparent insulating substrate, the Zn O/Ni O bilayer films was deposited on the mica sheet,the crystal structure and surface morphology were studied at different substrate temperatures;The preparation of n-Zn O/p-Ni O heterojunction devices on the flexible transparent substrate, was aimed to study the possible effet of piezotronics and piezo-phototronics;4. Used SF6 processed MoS2 chips and ZnO thin film deposited by PLD technology,we designed a p-Mo S2/n-Zn O heterojunction diode,The p-n diode exhibits high rectification ratio(3.4×104) and large reverse saturation current area(1.5 V). The heterojunction p-n diode presents good photo-response at the ultraviolet range.Additionally, the relevant photocurrent can be distinctly enhanced for more than four times with 23 MPa applied pressure owing to the piezo-photoronic effect.