Study on Preparation and Properties of P-type ZnMgO:In-N Film
|School||Chongqing Normal University|
|Keywords||RF magnetron sputtering p-type ZnMgO films Ion-implantation N-In codoped Annealing|
Zinc oxide（ZnO）is a direct wide band-gap semiconductor material with band gap of 3.4eV, the large exciton binding energy of 60meV, which is higher than other wide band gap materials such as GaN （21meV） or ZnSe （20meV）, also higher than thermal energy （26meV） at room temperature. So it has excellent conditions to launch blue or near ultraviolet ray. Moreover, when Magnesium is doped into ZnO, the band gap of ZnMgO thin films can be tuned by varying the content of Magnesium, so it could heightion the luminous clearly for application in ZnO/ZnMgO structure. the luminous of semiconductor lasers could covered the regional form ultraviolet light to blue light. Therefore, the study of ZnMgO film is very important and valuable.The key of ZnMgO film applied to ZnO/ZnMgO heterjunction, short-wavelength optoelectronic devices is obtain highly quality, reliable p-type ZnMgO films. However, problems associated with low solubility of acceptor dopants, high self-compensation effects made it difficult to realize highly stable and reproducible p-type ZnO films with excellent electronic properties. Theory research shows using donor-acceptor codoped ZnO can reduce the madelung energy and enhance the solubility of nitrogen . Based on above analysis, in the present dissertation, N-In codoped p-type ZnMgO films are prepared successfully.Zn1-xMgxO（0≤x≤0.09）films are fabricated on quartz glass substrates by radio frequency （RF） magnetron sputtering technique.The influence of varying Mg composition on the structure、optical and electrical properties of the Zn1-xMgxO films are investigated by x-ray diffractormeter （XRD）, optical transmission measurement and Hall measurement. It is found that all the films show good crystallization withc-axis orientation and a high optical transparency （≥80%） in the visible region. A blue shift in absorption edge indicates that the band gap increased as the increase of Mg content. Considering the conduction-band shifts to higher energy and increasing the activation energy of the defect donor states, the relationship between carrier concentration and Mg content is calculated, which is in agreement with the consequence of Hall measurement. In addition, We use the tantalite target fabricate ZnMgO:In thin films. Tantalite target was manufactured by ZnO、MgO and In2O3 powers. Combining with direct implantation of N+ and post-annealing in N2 gas, p-type ZnMgO films are obtained successfully. The ZnMgO:In-N thin films annealed at 575℃25min、27min show good p-type conductivity with the hole concentration of 1017-1018cm-3, and give a picture that shows the distribution diagram of p-type conduction conversion of ZnMgO:In-N films. X-ray photoelectron spectroscopy studies suggest that the presence of nitrogen and indium in the form of N–Zn、N–In and Mg-O bond in the codoped films, and the p-type conductivity of ZnMgO is attributed the formation of the InZn+2NO complex.