Dielectric properties of Li-doped ZnO thin films prepared by pulsed laser deposition

Abstract

ZnO is becoming more and more popular third-generation semiconductor for its wide band gap and large exciton binding energy. But the pure ZnO gradually can？ft meet the people？fs demands in nowadays, then impurity doping and the using of the defects which can improve and enlarge the properties are hot spot in nowadays. This article introduces the way of Li doped into ZnO. Thin films of Li-doped ZnO with different compositions (Zn1−xLixO, x = 0.02-0.2) have been prepared on heavily doped Si substrates by a pulsed laser deposition technique, and we get the good quality transparent conducting oxides thin film with a ferroelectric nature. Through many substantial tests, theoretical studies and comparisons to the conclusions in hand, our mainly contents as following: 1. We choose the Li element doped into the ZnO and the impurities are well doped into the ZnO; the impurities affect little to the structure of the ZnO. 2. The thin films are made by the PLD method, and the structure of the crystal in the thin film grows well follow the c-axis. The ferroelectricity of the thin film Zn0.88Li0.12O is observed in the P-E hysteresis loop test ,and Ec is 5.53 KV/cm and Pr is 0.186 ？？c/cm2 3. The permittivity of the Zn1-xLixO is involved with the temperature and the frequencies. And we also find a crest in the test around certain temperature, so we can call the change temperature Tc for short , for example, the Tc of the Zn0.85Li0.15O is about 95？？ 4. The optical transmission of the .Zn1-xLixO thin films are good, most are over 75%; through the calculation with the test dates, we can roughly get the academic thickness of the thin film, which is coincide with the actual result.