n-Hg_(0.80)Mg_(0.20)Te界面积累层中二维电子气的输运特性研究

通过变磁场霍耳测量研究了MBE生长的Hg0 .80 Mg0 .2 0 Te薄膜在 1 5— 2 5 0K温度范围内的输运特性 .采用迁移率谱 (MS)和多载流子拟合过程 (MCF)相结合的方法对实验数据进行了分析 ,由该方法获得的结果和ShubnikovdeHass(SdH)振荡测量的结果都证明材料中存在二维 (2D)电子和三维 (3D)电子 .其中 2D电子主要来自于Hg1-xMgxTe CdTe的界面积累层或Hg1-xMgxTe与真空界面附近的积累层 .3D电子迁移率随温度的变化关系表明了Hg1-xMgxTe中的电子散射机理与Hg1-xCdxTe中的非常相似 :在低温下电离杂质散射 (考虑了屏蔽效应 )起主导地位 ,而温度在 10 0K以上时 ,晶格散射占主导地位 .

STUDY ON TRANSPORT PROPERTIES OF TWO-DIMENSIONAL ELECTRON GASES IN n-Hg_(0.80)Mg_(0.20)Te INTERFACE ACCUMULATION LAYER

The transport properties in Hg 0.80 Mg 0.20 Te molecular beam epitaxy film has been studied in the temperature range from 1 5 to 250?K by variable magnetic|field Hall measurement.The experimental data have been analyzed using a hybrid approach consisting of the mobility spectrum(MS) technique followed by a multicarrier fitting(MCF) procedure.Both Shubnikov de Hass(SdH) Measurements and the hybrid approach show two| and three|dimensional electronic behaviors.Experimental results indicate that the two|dimensional electrons are due to an accumulation layer near the Hg 1-x Mg xTe|CdTe interface or the Hg 1-x Mg xTe|vacuum interface.Ionized impurity scattering of the three|dimension electron mobility dominates at low temperature(considering the screening effect) while lattice scattering dominates above 100?K.The scattering mechanism in Hg 1-x Mg xTe is very similar to that in Hg 1-x Cd xTe.