Tm2O3相对于Si的能带偏移研究

利用分子束外延系统在Si (001) 衬底上制备了单晶Tm₂O₃薄膜, 利用X射线光电子能谱研究了Tm₂O₃相对于Si的能带偏移. 得出Tm₂O₃相对于Si的价带和导带偏移分别为3.1 eV± 0.2 eV和1.9 eV± 0.3 eV, 并得出了Tm₂O₃的禁带宽度为6.1 eV± 0.2 eV. 研究结果表明Tm₂O₃是一种很有前途的高k栅介质候选材料. 关键词： 2O₃')" href="#">Tm₂O₃ X射线光电子能谱 能带偏移     

Amorphous Er2O3 films for antireflection coatings

This paper reports that stoichiometric, amorphous, and uniform Er2O3 films are deposited on Si(001) substrates by a radio frequency magnetron sputtering technique. Ellipsometry measurements show that the refractive index of the Er2O3 films is very close to that of a single layer antireflection coating for a solar cell with an air surrounding medium during its working wavelength. For the 90-nm-thick film, the reflectance has a minimum lower than 3% at the wavelength of 600 nm and the weighted average reflectances (400-1000 nm) is 11.6%. The obtained characteristics indicate that Er2O3 films could be a promising candidate for antireflection coatings in solar cells.     

Band Alignment and Band Gap Characterization of La2O3 Films on Si Substrates Grown by Radio Frequency Magnetron Sputtering

La2O3 films are grown on Si （100） substrates by the radio-frequency magnetron sputtering technique. The band alignment of the La203/Si heterojunction is analyzed by the x-ray photoelectron spectroscopy. The valence- band and the conduction-band offsets of La2 Oa films to Si substrates are found to be 2.40±0.1 and 1.66±0.3 eV, respectively. Based on 0 ls energy loss spectrum analysis, it can be noted that the energy gap of La203 films is 5.18±0.2eV, which is confirmed by the ultra-violet visible spectrum. According to the suitable band offset and large band gap, it can be concluded that La2O3 could be a promising candidate to act as high-k gate dielectrics.     

纳米硅结构中分裂能级对光电输运特性的影响

基于电子在分裂能级系统中同时存在的共振隧穿和子带输运过程,结合光生载流子作用提出了纳米硅结构中的光电输运理论模型.利用该模型计算了纳米硅结构在光照条件下的电流密度、电场强度及电子浓度分布.结果表明,光生电子在具有分裂能级的纳米硅中是以共振隧穿为主要输运方式.在此基础上,详细研究了光电流与吸收系数、外加偏压以及纳米硅层层数之间的关系,发现在特定的外界条件下光电流会出现跳变增加的现象,其物理原因是纳米硅结构中电场强度的二次分布.     

Annealing effects on the structure and electrical characteristics of amorphous Er2O3 films

Amorphous Er 2 O 3 films are deposited on Si (001) substrates by using reactive evaporation.This paper reports the evolution of the structure,morphology and electrical characteristics with annealing temperatures in an oxygen ambience.X-ray diffraction and high resolution transimission electron microscopy measurement show that the films remain amorphous even after annealing at 700 C.The capacitance in the accumulation region of Er 2 O 3 films annealed at 450 C is higher than that of as-deposited films and films annealed at other temperatures.An Er 2 O 3 /ErO x /SiO x /Si structure model is proposed to explain the results.The annealed films also exhibit a low leakage current density (around 1.38 × 10 4 A/cm 2 at a bias of 1 V) due to the evolution of morphology and composition of the films after they are annealed.     

含氧空位缺陷钨酸铋光催化产氢性能研究

新型半导体光催化剂钨酸铋是目前研究广泛的光催化剂,但因其电子空穴对易复合的问题,限制了光催化产氢性能。为解决这一问题,采用锂-乙二胺溶液在钨酸铋表面构筑可控氧空位缺陷和金属缺陷。通过材料表征对比了钨酸铋经锂-乙二胺处理前后的变化,并对两者进行了产氢速率测试。钨酸铋在经过锂-乙二胺处理过后产生了氧空位缺陷和降价的金属中心,材料颜色从原先的黄白色转变为黄棕色,增强了光吸收能力。颗粒的主体结构以及物质成分并未发生变化,仍保持花球状颗粒结构,但处理后钨酸铋颗粒表面原先的光滑的片状结构变得粗糙,且方形纳米薄片锋利边缘变光滑,提高了光催化反应面积。这些变化使锂-乙二胺处理后的钨酸铋光催化产氢性能相比未处理之前得到了一定的提升。     

Microstructure of Epitaxial Er2O3 Thin Film on Oxidized Si （111） Substrate

Er2O3 thin films are grown on oxidized Si （111） substrates by molecular beam epitaxy. The sample grown under optimized condition is characterized in its microstructure, surface morphology and thickness using grazing incidence x-ray diffraction （GIXRD）, atomic force morphology and x-ray reflectivity. GIXRD measurements reveal that the Er2O3 thin film is a mosaic of single-crystal domains. The interplanar spacing d in-plane residual strain tensor ell and the strain relaxation degree ε are calculated. The Poisson ratio μ obtained by conventional x-ray diffraction is in good agreement with that of the bulk Er2O3. In-plane strains in three sets of planes, i.e. （440）, （404）, and （044）, are isotropic.