窄禁带N型掺杂HgCdTe中自由载流子的奇特性质

研究已表明掺杂HgCdTe中不存在对于自由载流子等离子体振荡的朗道阻尼,本文进一步研究了HgCdTe掺杂及随之产生的简并对自由载流子能量色散关系的影响,并将这种影响计入自由载流子的介电函数后,从理论上证明了掺杂窄禁带半导体中不存在朗道阻尼的现象是由于自由载流子能量色散关系变化引起其运动行为变化所致。     

窄禁带半导体等离子体反射边的研究

窄禁带和一些零禁带半导体的能带结构可以用Kane模型很好地描写。为观察等离子体振荡,电子浓度必须足够高,此时E_f附近的能带呈线性,从而导致等离子体振荡和单个载流子激发之间能量耦合的消失。由于较强的等离子体振荡,在其反射谱上出现较陡的等离子体反射边以及反射边底部较尖锐的反射极小值。     

用红外光吸收方法测定Hg_(1-x)Cd_xTe中电离杂质浓度和微沉淀物

由于动量守恒和能量守恒的要求,固体中自由载流子的光吸收过程总是伴随着声子或电离杂质散射过程。声子和电离杂质散射的强度很大程度上决定了自由载流子吸收系数。对于像Hg_(1-x)Cd_xTe这样的极性混晶半导体,采用唐文国的双模Callen有效电荷就可以计算出光学声子的散射强度,对于给定的样品,它仅和温度有关。声学声子和无序散射都微乎     

用吸收和反射谱的方法测定半磁半导体HgSe:Fe的重要参数(英文)

Infrared measurements have been performed on semimagnetic semiconductor HgSe:Fe with concentrations of iron from 2 ×1018cm-3 to 7×1019cm-3 in the wavelength region of 300 cm-1 to 2500 cm-1 and the temperature range from 11K to 300K, for the absorption spectra, and 300K, for the reflectivity spectra, respectively.Calculations of free carrier absorption coefficient and reflectivity based on Drude theory have also been carried out.It was found that the calculated values of both absorption coefficient and reflectivity agree very well with the measured values. This proves that Drude theory can be used to explain the free-carriers absorption and reflectivity of HgSe:Fe. Thus, the parameters of material, such as plasma frequecy, high frequency dielectric constant and damping constant, can be then obtained from the fitting of theory to experiment. Furthermore, two other physical parameters, i.e. the concentration of free carriers and effective mass averaged over energy band, can be evaluated.     

HgSe：Fe的红外光谱和自由载流子散射

测量了掺Fe浓度为1.5×10~(18)～7×10~(19)cm~(-3)的HgSe:Fe样品在中红外波段内的室温透过率和反射率,由此看出Fe浓度大于或小于4×10~(18)cm~(-3)时吸收系数,迁移率和吸收截面的性质明显不同,用Fe的空间有序化模型解释了实验结果。