Dc Magnetron Sputtering In-n Co-doped P-type Zno Thin Films

As new Ⅱ-Ⅵ semiconductor material, ZnO has a lot of ideal properties and is considered as the promising opto-electronic material, for application in LEDs, LDs and UV detector. Compared with GaN, ZnO have many advantages:(1)much higher excition binding energy(60meV)than that of GaN(24meV), which promises ZnO strong excitonic emission at room temperature,(2)ZnO can be fabricated at a much lower temperature,and a lower cost,(3)can use different substrates,(4) ZnO is strong anti- radiative,can be used under harsh environments.Thus ZnO is promising acting as a new choice for opto-electronic devices besides GaN.ZnO is a native n type material, there are some reports that good n type ZnO films have been preparation with doping Al, Ga and so on, but it is hard to fabricate P type ZnO films because of self-compensation and low solubility of acceptor. N is regard as the most appropriate acceptor, and some groups have succeed in fabricating p type ZnO films but the films' qualities are not good or the films are unstable.Few years ago, codoping method is proposed for prepatation for p type ZnO films. Theoretically, we can acquire stable p type ZnO films with high carrier concentrations, low resistance by codoping method. Our lab had succeeded in fabricating it by Al-N codoping method. In this paper, we fabricate p-type ZnO film by N-In codoping, which can be use for opto-electronic devices that based for ZnO.The main content of the thesis is as follows:1. Depositing In-N co-doped ZnO films by DCMS, when the substrate's temperature is 520℃, the hole carrier concentration is 2.58 × 10¹⁸ cm^-3 , resistance is 3.91 Ω cm, and Hall mobility is 0.62 cm²V^-1s^-1.2. Through XRD analysis, the minimum of 2-theta is 0.241, which is close to the reported 0.20 of pure ZnO films. That means the co-doped films have a good crystal structure.3. Researching the influence of the In content on the films' grain size, more the In content, smaller the size, and through SEM test, we can see the films' surface will be most smooth at a appropriate substrate temperature.4. Through cross-section SEM test, the film's thickness is homogeneous, and is about 125nm when the substrate's temperature is 520℃.5. Through Hall test, the electronic properties of co-doped films are improved,compared with N-doped ZnO films, the hole carrier concentration increases 3 order magnitude and the resistance decreases 2 order magnitude.6. The electronic properties are almost the same after 30 days, which shows the/? type co-doped film's electronic properties are stable.7. Reasearching the influence of substrate's temperature on co-doped films, at lower temperature, the films are n type with high resistance, at too high temperature, the films are n type with low resistance, when the temperature is between 480-540°C,the films are/? type with low resistance.8. The average transmittance in the visible region (A,=400-800nm) is about 90%. As the substrate's temperature increase from 480 °C to 520 °C, the absorption edge shifts from 379nm to 358nm, but then towards longer wavelength side at a higher temperature.