单频导纳谱法测量锗硅量子阱的能带偏移

提出了用单频导纳谱法测量储硅单量子阶的能带偏移，与常规的多频导纳谱相比，它只需测一个频率的导纳谱就能得到更精确的实验结果。用该方法对Ｓｉ／Ｇｅ_０．３３Ｓｉ_０．６７／Ｓｉ单量子阱进行测试，得到激活能为Ｅ_a＝０．２０ｅＶ。为了计算出能带偏移值，必须能准确确定具有单量子阱结构样品中的费密能级位置，由于在单量子阱结构中费密能级的位置与阱材料、垒材料的掺杂浓度、阱的高度（即能带偏移）及温度等几个因素均有关。为此，本文通过解泊松方程，计算出结合本文样品关键词：

MEASUREMENT OF THE BAND OFFSET IN GexSi1-x/Si SINGLE QUANTUM WELL BY USING SINGLE FREQUENCY ADMITTANCE SPECTROSCOPY

A single frequency admittance spectroscopy technique is introduced for determining the band discontinuity on Si/Ge_xSi_1-x/Si single quantum well (SQW). By using this method, the more accurate experimental results can be obtaind from a single frequency admittance spectrum. For an alloy with composition x=0.33，we get the activation energy E_a＝0.20eV. In order to obtain the value of the band offset，it is necessary to determine the position of Fermi level which depends on the dopam concentration inside and outside the well, the band offset of hetero-interface and temperature. By solving Poisson equation, we get the energy band diagram and Fermi level of the test sample. It is shown that the Fermi level lies about 40 meV above the top of valance band in the well. And due iv the carrier transfer at the hetero-interface, the carrier concentration (about ２×１０¹⁷ｃｍ^－３) in the well is one order large than dopant concentration(1×１０¹⁶ｃｍ^－３). The energy bands at two sides of the interfaces are bent by about 0.006 eV in the well and O.11eV in the barrier, hence the valance band offset can be calculated as 0.16eV. The accuracy of this technique can also be verified from reconstruction of C-T and G-T curves by cumputer simulation.