Crystal Characterization by Far-infrared Magneto-optical Absorption

本工作采用毫米波和亚毫米波磁吸收测量技术，为研究薄膜的能带结构、载流子输运、动力学等提供了方法，已用于Ge、InSb、GaAs和AnSe等材料的直接表征。实验结果如下：1）首次在ZnSe中观察到了重空穴回旋共振。通过X射线衍射分析和偏光显微镜观察，我们发现某些ZnSe晶体具有无数孪晶界的多镶嵌结构。这些边界显然导致形成潜在的威尔斯井，这是二维特征的原因。3）通过GaAs的时间分辨回旋共振，研究了GaAs的电子-声子散射的温度依赖性，研究了电子-中性施主散射的磁场和浓度依赖性以及载流子-载流子散射的电子密度依赖性。4）磁致散射的时间分辨测量为了研究p型InSb样品中自旋热电子的弛豫，进行了光激发电子的光吸收实验。结果表明，自旋翻转时间主要由施主杂质散射决定，与它们的电荷状态无关。

In this work,millimeter and submillimeter wave magneto- absorption measurements,which illuminate the way to study the band structure,carrier transport,kinetics etc.,has been used to make a direct characterization of such meterials as Ge,InSb,GaAs and AnSe. Experimental results are as follows.1)For the first time,heavy hole cyclotron resonance has been observed in ZnSe. The resonance is almost isotropic and corresponds to a polaron effective mass of m_p=1.04m_o.2)Through the X-ray analysis and microscopic observation with polarizers,we found multimosaic structure of numberless twin-crystal boundaries for some ZnSe crystals. These bound- aries are evidently leading to a formation of potential wells that are responsible for the 2D character. This character of the magneto-optical absorption signal show up for above-mentioned samples.3)Through the time-resolved cyclotron resonance of GaAs, the temperature dependence of electron-phonon scattering, magnetic field and concentration dependence of the electron- neutral donor scattering and electron-density dependence of carrier-carrier scatering have been investigated.4)Time-resolved measurements of the magneto-optical absorption due to photoexcited electrons have been carried out in order to investigate the relaxation of spin hot electrons in p-type InSb samples. It was found that the spin flipping time is primarily determined by donor impurity scattering and is independent of their charge states.