Growth of In-Doped PbTe Films on Si Substrates

Data on the evaporation behavior of Pb_{1 – x} In _x (0.10 x 0.70) melts were used to devise a procedure for the growth of vapor-phase In doped PbTe thin films on Si substrates. This approach offers the possibility of growing single-phase, homogeneous Pb_{1 – y} In _y Te films of controlled composition by adjusting the composition and temperature of Pb_{1 – x} In _x (0.10 x 0.50) melts. X-ray diffraction characterization demonstrates that the films grown on Si with no oxide layer consist of slightly misoriented crystallites, with their (100) axes normal to the film surface, whereas the films grown on substrates covered with a SiO₂ layer are polycrystalline, with a strong (100) texture.     

Transport Properties of Ga-Doped PbTe Thin Films on Si Substrates

Thin PbTe films on Si substrates were doped with Ga via annealing in the vapor produced by heating a Ga(l) + GaTe(s) mixture (GaTe(s) + L ₁+ Vequilibrium). Electrical measurements showed that the vapor-phase doping reduced the hole concentration in the films by more than two orders of magnitude. IR irradiation was found to reduce the resistivity of the PbTe films by a factor of 40–100. The films annealed in the vapor over GaTe(s) + L ₁for the longest time exhibited an anomalous temperature variation of resistance, which was interpreted as due to the limited Ga solubility in PbTe.     

射频磁控溅射法制备碲化铅薄膜的X射线衍射分析

采用射频磁控溅射法,在单面抛光的Si(111)衬底上制备了PbTe薄膜,利用X射线衍射法分析了溅射工艺参数如溅射功率、溅射时间、衬底温度以及退火温度对PbTe薄膜的结晶质量的影响。结果表明:在溅射功率为30W,溅射时间为10 min,衬底未加热时制备的薄膜具有最好的〈100〉方向的择优取向性;退火处理可以改善薄膜的结晶质量,并且退火温度越高,薄膜的结晶质量越好。     

Ga Doping of Thin PbTe Films on Si Substrates during Growth

In depositing thin PbTe films onto Si substrates by a modified hot-wall method, Pb_{1 – x} Ga _x melts were used as Ga vapor sources in combination with separate Pb and Te sources. Data on the vaporization behavior of Pb_{1 – x} Ga _x melts were used to devise a new technique for reproducible growth of PbTe/Si and PbTe/SiO₂/Si structures. The lattice parameter of the PbTe films was found to vary nonmonotonically with Ga content, which was interpreted as evidence that the dopant can be incorporated by different mechanisms. Conductivity and Hall effect measurements between 77 and 300 K reveal a nonmonotonic variation of carrier concentration with doping level and suggest that Ga is an amphoteric impurity in narrow-gap IV–VI semiconductors.     

TC4钛合金表面阳极氧化制备TiO_2多孔膜的实验研究

以硫酸为电解液,钛合金(TC4)为阳极,不锈钢片为阴极,采用恒压的氧化方式在钛合金表面获得TiO2多孔膜。通过扫描电镜(SEM)观察了多孔膜的微观形貌并用X射线衍射(XRD)对覆在钛合金基体上的氧化膜进行了物相分析,研究了氧化工艺参数电压、阳极氧化时间和硫酸浓度对TiO2多孔膜相组成的影响。结果表明:TC4钛合金阳极氧化获得的氧化膜为非均一平面的TiO2多孔膜,且膜的孔径分布在90~240nm,XRD分析表明在不同的氧化工艺参数下氧化膜均由锐钛相和金红石相双相晶型组成。在0.5mol/L硫酸溶液中,电压高于100V或氧化时间长于5min即出现锐钛相和金红石相TiO2,随着电压的升高和时间的增长金红石相TiO2的含量逐渐增加;在恒压120V时,硫酸溶液浓度为0.3mol/L即出现锐钛相和金红石相TiO2,随着硫酸浓度的提高金红石相TiO2的含量先增加后减少。     

Structural Perfection of PbTe Films Doped with Indium during Growth on Si Substrates

Pb_{1 - y} In _y Te films doped during growth are produced by a modified hot-wall method. According to x-ray diffraction and electron microscopy data, the films withy _tot < 0.012 are single-phase. The films with y _tot > 0.014 consist of two (PbTe + InTe) or three (PbTe + InTe + In₂Te₃) phases. The 583-K indium solubility in PbTe is determined in the ternary system Pb-In-Te. The results indicate that two pseudobinary joins, PbTe-InTe and PbTe-In₂Te₃, must be examined in assessing the In solubility in PbTe.     

钛合金表面微弧氧化技术的研究

微弧氧化是一项在有色金属表面原位生长陶瓷膜的新技术,利用该技术可在钛合金表面生成耐磨、耐蚀、耐高温以及电绝缘性能优异的陶瓷膜层.介绍了微弧氧化技术的基本原理、钛合金微弧氧化的发展及现状,并提出了钛合金表面微弧氧化技术发展的新思路.     

An Ellipsometric Study of the Oxidation of Thin Copper Films in Oxygen

The thermal oxidation of thin copper films deposited on single-crystal silicon was studied by ellipsometry. The optical properties of the oxide layers grown at 420–470 K over a period of up to 150 min were found to vary with layer thickness in a complex manner. The results were analyzed in terms of single- and two-layer models. The oxidation kinetics were shown to follow a parabolic rate law. The apparent activation energies for different stages of oxidation were evaluated with allowance for the self-organization of the interfacial layer.     

Ag-BaO光电发射薄膜表面结构的STM研究

利用真空沉积方法制备了Ag-BaO光电发射薄膜,第一次用扫描隧道显微镜(STM)研究了Ag-BaO薄膜的表面结构,得到了高分辨的表面形貌像。介绍了Ag-BaO薄膜微区表面复杂的形态结构,并将测量结果和Ag-BaO薄膜的TEM像作了比较,分析了这些结构对光电发射的影响。