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本文系统研究了厚度约1μm的Al掺ZnO(AZO)薄膜的低温电子散射机制.研究发现,薄膜在较高温区的电阻温度系数为正值,且载流子浓度在2~300K范围内不随温度而改变,表明薄膜具有简并半导体的电输运性质.通过测量薄膜在4~35K范围不同温度下的磁电阻,获得了低温下退相干散射率与温度的关系.与现有非弹性散射理论比较发现,仅由电子-声子散射并不能解释AZO薄膜低温下非弹性散射率与温度的依赖关系,除电子-声子散射外,必须同时考虑小能量转移电子-电子散射的贡献,这与薄膜较低的载流子浓度相关(我们的薄膜载流子浓度低于8×1020 cm~(-3)).我们的结果一方面表明电子-声子散射和电子-电子散射可以在三维无序导体中并存,另一方面从实验上定量地验证了关于电子-声子散射率与小能量转移电子-电子散射率的理论.
In this paper, the mechanism of low-temperature electron scattering of Al-doped ZnO (AZO) thin films with a thickness of about 1μm has been systematically studied. It is found that the temperature coefficient of resistance of the film is positive at higher temperature and the carrier concentration does not vary with the temperature The results show that the film possesses the electrical transport properties of degenerate semiconductors.The dependence of the backscattering speckle at low temperature on temperature is obtained by measuring the magnetoresistance of the films at different temperatures in the range of 4 to 35 K. Compared with the existing inelastic scattering theory It is found that electron-phonon scattering alone can not explain the dependence of temperature on the inelastic scattering rate of AZO films. In addition to electron-phonon scattering, the contribution of electron-electron scattering with small energy transfer must be taken into consideration. The film has a lower carrier concentration (our film carrier concentration is less than 8 × 1020 cm -3) .Our results show that on the one hand, electron-phonon scattering and electron-electron scattering can be performed in three-dimensional On the other hand, the theory of electron-phonon scattering rate and small energy transfer electron-electron scattering rate has been experimentally quantitatively verified.