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在高强度光激发的Ge、GaAs和ZnSe中观察到电子-空穴等离子体.采用远红外磁光吸收和光致发光两种手段研究了等离子体的空间膨胀.将Ge的远红外磁光吸收谱中的一个低磁场峰指认为快速扩展的电子-空穴-等离子体中的空穴在价带间的跃迁,用磁场限制扩散模式解释了时间和空间分辨测量结果.半绝缘GaAs中电子-空穴-等离子体的膨胀与扩散常数有关,而扩散常数取决于激发强度,这就提示了膨胀是由于“声子风”(phonon wind)而引起的.在用MOVPE方法生长的ZnSe外延层中也观察到均匀的等离子体.用非-k选择定则能很好地拟合光致发光谱线型,多体效应引起的带隙收缩与在其它Ⅱ-Ⅵ族化合物中观察到的类似,并首次观察到ZnSe外延层中的电子回旋共振.
Electron-hole plasmas were observed in high-intensity photoexcited Ge, GaAs and ZnSe. The far-infrared magneto-optical absorption and photoluminescence were used to study the space expansion of the plasma. One of the low magnetic field peaks indicates the valence-band transition of voids in the rapidly expanding electron-hole plasma, which accounts for the time and space resolved measurements using a magnetic field-limited diffusion mode. The hole-to-plasma expansion is related to the diffusion constant, and the diffusion constant depends on the excitation intensity, which suggests that the expansion is due to “phonon wind.” In the ZnSe epitaxial layer grown by the MOVPE method A uniform plasma was observed. The fitting of the photoluminescence spectra was well fitted by the non-k selection rule, and bandgap shrinkage caused by the multibody effect was similar to that observed for other II-VI compounds and The electron cyclotron resonance in the ZnSe epitaxial layer was observed for the first time.