Synthesis of P-type ZnO Thin Films Using the Successive Ionic Layer Adsorption and Reaction Method
|School||Huazhong University of Science and Technology|
|Course||Microelectronics and Solid State Electronics|
|Keywords||p-type zinc oxide Successive ionic layer adsorption and reaction method Optoelectronic properties|
ZnO is a direct band gap II-VI compound semiconductor materials in the field of optoelectronic applications and broad prospects, is expected to replace the GaN used to a new generation of short-wavelength light emitting devices . But difficult to prepare p-type ZnO , which restricts the development of ZnO has become the bottleneck of its application . In this paper, the completion of the successive ionic layer adsorption reaction of ZnO thin films . By comparing the experimental conditions , we propose that the optimum deposition conditions . Ethanolamine as the alkaline reagent added to the the zinc ammonia solution , can reduce the dissolution of the film . The two - step annealing treatment , the volatilization of the residual organics in the film and the film grain recrystallization process separately , can form a better crystal structure . The in continuous ion layer adsorption and reaction method introducing heat treatment process , and greatly improve the performance of the ZnO thin film , the film formed has good c-axis preferentially oriented , transparent and conductive properties has also been significantly improved . Li as dopant is added to ZnO , the p - type ZnO films can be prepared when the doping concentration of 5% . Combination of X-ray diffraction , absorption spectroscopy , photoluminescence spectra and Hall-effect analysis , we studied the mechanism of action of Li in ZnO , Li substitutional doping low concentrations exist , will form fill high concentration doping gap , the resulting donor impurity cause the thin film of p-type to n - type . O2 annealing atmosphere and the annealing temperature to reduce the donor impurity in the film , thus promoting the formation of p-type ZnO films . The crystal structure analyzed Li doped forms exist in the ZnO and the formation of a grain size of 17.0 1 < / sup> 8.8 nm , the lattice constant a, c 3.25 (A | °) and 5.20 , respectively ( A | °), stacking layers of about 33 layers . The optical performance analyzes ZnO band gap is mainly distributed in the 3.27 3 sup> .29 eV, its light curve contains four emission peak . The final preparation of the resistivity of p-type ZnO material 1.04Ωcm, Hall mobility of 0.75 cm 2 sup > / Vs and carrier concentration is 8.02 × 18 < / sup> cm < sup > -3 sup>. Through the analysis of the PL spectrum , the formation of acceptor level energy of 91 meV.