Composition effect on the structure and optical parameters of Ge–Se–Te thin films

The present work reported the influence of Ge content variation on the optical properties of Ge_xSe₅₀Te_50-x (x=0, 5, 15, 20, 35 at%). Vacuum thermal evaporation technique was employed to prepare amorphous Ge_xSe₅₀Te_50−x thin films. The stoichiometry of the chemical composition was checked by energy dispersive X-ray spectroscopy (EDX), whereas the thin films structure was determined by an X-ray diffraction and a scanning electron microscope (SEM). The optical absorption measurements were performed at room temperature in the wavelength range of 200–900 nm. Many optical constants were calculated for the studied thin films utilizing the optical absorption data. It was observed that the optical absorption mechanism follows the rule of the allowed direct transition. The optical band gap was found to increase from 2.31 to 2.60 eV as the Ge content increases from 0 to 35 at%. This result was explained in terms of the chemical bond approach.     

利用ArF准分子激光退火获得小锗量子点的研究

使用ArF准分子激光脉冲对UHV/CVD条件下生长的Ge量子点进行退火处理,获得了底宽为20～25nm的光致量子点(LIQD),远小于退火前的量子点大小.LIQD的密度约为6×1010cm-2.分析表明,在ArF准分子激光脉冲作用下,退火样品只有表面扩散,并没有体扩散.激光脉冲对表面Ge原子的扩散控制导致了Ge量子点形貌发生了巨大的改变.该方法为获得高密度小尺寸的Ge量子点提供了新的途径.采用原子力显微镜对光致量子点的表面形貌进行了研究.     

超薄体MOSFET的结构优化

对U TB器件的各结构参数进行了优化,给出了UTB器件设计的指导方向.在U TB器件的设计中,有三个重要参数,即器件的源漏提升高度、锗硅栅(Gex Si1 - x)中Ge含量的摩尔百分比和硅膜的厚度,并对这三个结构参数对器件性能的影响进行了模拟分析,给出了器件各结构参数的优化方向,找出了可行Ge含量的摩尔百分比和可行硅膜厚度之间的设计容区.通过模拟分析发现,只要合理选择器件的结构参数,就能得到性能优良的U TB器件     

不同气体退火La_2O_3栅介质Ge MOS电容的电特性

采用电子束蒸发方法,在Ge衬底上淀积La_2O_3高k栅介质,研究了O_2、NO、NH_3和N_2不同气体退火对MOS电容电特性的影响。测量了器件的C-V和I-V特性,并进行了高场应力实验。结果表明La_2O_3在N_2气氛中退火后,由于形成稳定的LaGeO_x而有效地降低了Q_(ox)和D_(it),从而获得低的栅极漏电流,同时获得较高的栅介质介电常数(18)。     

GeSi/Si多层异质外延载流子浓度的分布

通过实验确定了一种与 Gex Si1 - x合金表面具有良好电化学界面的电解液 ,利用电化学 C- V方法研究了多层Gex Si1 - x/ Si异质外延材料的载流子浓度纵向分布 .实验结果表明 :采用这种电解液 ,利用电化学 C- V载流子浓度纵向分布测量仪检测 Gex Si1 - x/ Si异质材料的载流子浓度纵向分布 ,重复性好 ,可靠性高     

Activation Cross Sections for (n,p) and (n, α) Reactions on Nd,Sm, Yb and Lu at 14.6 MeV

Activation cross sections for the (n, p) and (n, α) reactions of Nd, Sm, Yb and Lu have been measured at 14.6 MeV by using a Ge(Li) γ-ray detector. The following cross sections (in millibarns) have been obtained: ¹⁵⁰Sm(n, p) ¹⁵⁰Pm, 7.19±1.01; ¹⁷³Yb(n, p) ¹⁷³Tm, 13.5±2.8; ¹⁷⁵Lu(n, p) ¹⁷⁵Yb, 18.5±2.2;¹⁴⁶Nd(n,α) ¹⁴³Ce, 4.42±0.47; ¹⁵²Sm(n, α) ¹⁴⁹Nd, 2.81±0.42; 174Yb(n, α)¹⁷¹Er, 1.22±0.23 and ¹⁷⁶Lu(n, α)¹⁷³Tm, 2.30±0.57. The results are compared with predictions based on the evaporation, the pre-equilibrium and other models. The present experimental (n, p) cross sections agree fairly well with the pre-equilibrium model predictions. A comparison made between the experimental (n, α) cross sections and the predictions of the pre-equilibrium model suggests the existence of a mechanism of pre-equilibrium emission in the (n, α) reaction in this mass region.     

一步热压法制备N型Si80Ge20及其热电性能

采用一步热压法制备了N型Si80Ge20Px(x=0.2、1.0、2.0),通过改变P掺杂优化载流子浓度,对样品进行物相分析与微观结构分析,测试并比较了样品在30～800℃下的热电参数.结果表明:一步热压法可实现硅锗固相反应合金化,制备的Si80 Ge20结构致密、组分均匀;随着P掺杂增加,Si80Ge20Px的电导率...     

Sn掺杂对SixSb100–x相变薄膜结晶行为的影响

目的 通过掺杂不同含量的Sn,提升SixSb100–x相变薄膜的结晶温度、热稳定性和相转变速度,得到一种环境友好型无Te相变薄膜材料.方法 利用三靶磁控共溅射的方式制备掺Sn的SixSb100–x相变薄膜,并采用真空四探针测试系统,得到电阻-温度数据以及不同升温速率下的电阻数据,从而通过Kissinger和Arrhen...