Carrier dynamics in bulk ZnO. I. Intrinsic conductivity measured by terahertz time-domain spectroscopy
Carrier dynamics in bulk ZnO. I. Intrinsic conductivity measured by terahertz time-domain spectroscopy
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DOI：
10.1103/physrevb.80.235205
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发表时间：
2009-12-01
影响因子：
3.7
通讯作者：
Schmuttenmaer, Charles A.
中科院分区：
文献类型：
--
作者：
Baxter, Jason B.;Schmuttenmaer, Charles A.
利用太赫兹时域光谱技术测量了ZnO晶片的远红外吸收和折射率随温度的变化关系。伴随的频率依赖性复合电导率给出了电子动力学的准确图像，因为测量的0.2-2.5 THz范围包含了散射率。的频率依赖性的电导率示出的Drude模型预测的一般趋势，但具有显着的偏差，更好地拟合的广义Drude模型，它允许的载流子弛豫时间的分布。电导率随着温度的升高而增加，因为电子从浅施主态被热激活，计算出的施主能量为27 meV，密度为1.4x10（17）cm（-3）。测得的迁移率约为2000 cm（2）V（-1）s（-1），在60-120 K温度范围内，迁移率变化不大。
Far-infrared absorption and refractive index of a ZnO wafer were measured as a function of temperature below 120 K using terahertz (THz) time domain spectroscopy. The accompanying frequency-dependent complex conductivity gives an accurate picture of electron dynamics because the measured range of 0.2-2.5 THz brackets the scattering rate. The frequency-dependent conductivity shows the general trends predicted by the Drude model but with significant deviations that are better fit by the generalized Drude model, which allows for a distribution of carrier relaxation times. Conductivity increases with increasing temperature as electrons are thermally activated from shallow donor states, with calculated donor energy of 27 meV and density of 1.4x10(17) cm(-3). Mobilities of similar to 2000 cm(2) V(-1) s(-1) are measured and do not vary significantly with temperature over 60-120 K.