溅射功率对NiO薄膜性质的影响

在室温条件下,采用射频磁控溅射的方法在石英衬底上制备了NiO薄膜,深入研究了不同溅射功率对NiO的结构、光学和电学特性的影响。随着溅射功率的升高,NiO薄膜逐渐由非晶态薄膜转变成具有(111)择优取向的晶态薄膜,同时发现NiO薄膜在可见光区透过率较大,而在紫外光区透过率减小;随着溅射功率的升高,薄膜在可见光区域和紫外区域的光学透过率均明显减小,同时禁带宽度也减小,但导电性增强。     

压力对NiO晶体结构及电子结构影响的理论研究

采用密度泛函理论的方法研究了不同压力条件下立方结构NiO氧化物的晶格结构、稳定性和电子结构。计算结果表明,NiO氧化物的晶格参数逐渐减小,键长变小,对称性保持不变;体系费米能先降低后增加;零压力下其存在着0.46eV的间接带隙,费米能级附近的状态密度较低,随着外压力的增加,带隙先减小再增大,费米能级附近的态密度先增大再减小。分析结果表明,随着外压力的增加,NiO氧化物价带顶附近的载流子有效质量先增大再减小;导带底的载流子有效质量均较小。外界加力还改变了NiO体系的电子分布情况。     

强电场中铯原子双光子光电离光谱研究

报道了对铯原子在双光子激发条件下的强电场光电离光谱进行实验研究的结果。发现钩原子较大量子亏损导致的核心效应可影响到场电离阈值以上的光谱特性，但对零场阈值附近强场共振特性的影响可以忽略。     

带有AB环的T型结构中的电子输运性质

采用一维量子波导理论研究了带有AB环的类T型结构中的电子输运。在满足波函数的连续性以及电流的闭合性的情况下,得出了透射系数的解析表达式,并根据此表达式分析了电子的输运特性。结果显示：左右端的透射系数随磁通的变化产生典型的AB振荡。当改变中间的入射点的位置X时,左出射端的透射系数的大小随之改变,右输出端除 附近外,均产生与磁通无关的全反射现象。入射点位置X的变化对透射系数的影响出现一种周期性的调制现象。体系结构轻微的偏离对系统的输运特性影响不大。     

Be掺杂对ZnO电子结构和光学性质的影响

基于密度泛函理论（DFT）第一性原理计算了Zn1-xBexO化合物的电子结构和光学性质. 计算结果表明Zn1-xBexO带隙随掺杂浓度的增加而变大. 这种现象主要是由于价带顶O2p随掺杂量x的增加几乎保持不变,而Zn4s随掺杂量x的增加向高能端移动. 光学介电函数虚部计算结果表明：在2.0, 6.76eV位置随掺杂浓度的增加峰形逐渐消失,是由于Be替代Zn导致Zn3d电子态逐渐减少所致;而9.9eV峰形逐渐增强,是由于逐渐形成的纤锌矿结构BeO的价带O2p到导带Be2s的跃迁增加所致.     

Be掺杂对ZnO电子结构和光学性质的影响

基于密度泛函理论(DFT)第一性原理计算了Zn1-xBexO化合物的电子结构和光学性质.计算结果表明Zn1-xBexO带隙随掺杂浓度的增加而变大.这种现象主要是由于价带顶O2p随掺杂量x的增加几乎保持不变,而Zn4s随掺杂最x的增加向高能端移动.光学介电函数虚部计算结果表明:在2.0,6.76eV位置随掺杂浓度的增加蜂形逐渐消失,是由于Be替代Zn导致Zn3d电子态逐渐减少所致;而9.9eV峰彤逐渐增强,是由于逐渐形成的纤锌矿结构Beo的价带O2p到导带Be2s的跃迁增加所致.     

半导体纳米结构的新光电子学性质

纳米光子学国际会议于 1 999年 3月在俄罗斯科学院微结构物理研究所的所在地下诺夫戈罗德举行。这已是有关半导体纳米结构物理的第二次会议。第一次会议于 1 998年召开。会上讨论两个方向的现状。第一 ,与以硅 (Si Ge、Si/A3B5、Si/Ge/C、Si/Ge/Sn、Si/Si O2 量子阱和量子点 )、多孔硅和含有稀土元素的纳米晶体硅为基础的异质结构的光电子学性质基础有关的物理现象 ,相应的纳米结构生长工艺和特性 ;第二 ,在具有量子阱的半导体结构中的热载流子在强电场和磁场中的非平衡、反转分布及带内光学跃迁的物理问题 ,包括反转机理和在中、远红…     

缺陷对石墨烯电子结构的影响

基于第一性原理计算方法,通过密度泛函理论（DFT）和广义梯度近似（GGA）对本征及含有缺陷的石墨烯超晶胞进行了电子结构的计算,研究了多种缺陷对石墨烯电子结构的影响。研究发现,多种缺陷均使石墨烯能带在费米能级附近出现缺陷态对应的能带,并导致其能隙有不同程度的增大,而且与之对应的态密度也随之发生相应的变化。其中,Stone...     

HEMT结构材料中二维电子气的输运性质研究

本文通过变温的Ｈａｌ测量系统地研究了ＧａＡｓ基ＨＥＭＴ和ＰＨＥＭＴ以及ＩｎＰ基ＨＥＭＴ三种结构材料的电子迁移率μｎ和二维电子浓度ｎｓ．仔细地分析了不同ＨＥＭＴ结构材料的散射机制对电子迁移率的影响以及不同ＨＥＭＴ材料结构对电子浓度的影响．研究结果表明ＩｎＰ基ＨＥＭＴ的ｎｓ×μｎ值比ＧａＡｓ基ＨＥＭＴ和ＰＨＥＭＴ的ｎｓ×μｎ值都大,说明可以用ｎｓ×μｎ值来判断ＨＥＭＴ结构材料的性能好坏．     

电场下超晶格GaAs/Ga_(1-x)Al_xAs[111]的电子结构

用有效质量理论研究了GaAs/Ga_(1-x) Al_xAs[111]超晶格在外加电场下的电子结构.具体计算了超晶格的子能带色散关系曲线,子能级随外加电场的变化,并且计算了k_u=0的光跃迁矩阵元平方随电场的变化.与零电场情况相比,发现在k_u≠0处子能带的二重简并解除.随电场的增大,△n=0的跃迁减小,而△n≠0的跃迁增大.考虑单轴压力效应后,轻空穴和重空穴的能级位置发生下降和上升.     

Effects of vertical electric field and compressive strain on electronic properties of bilayer ZrS2

Using first-principles calculations, including Grimme D2 method for van der Waals interactions, we investigate the tuning electronic properties of bilayer zirconium disulfides (ZrS₂) subjected to vertical electric field and normal compressive strain. The band gap of ZrS₂ bilayer can be flexibly tuned by vertical external electric field. Due to the Stark effect, at critical electric fields about 1.4 V/Å, semiconducting-metallic transition presents. In addition, our results also demonstrated that the compressive strain has an important impact on the electronic properties of ZrS₂ bilayer sheet. The widely tunable band gaps confirm possibilities for its applications in electronics and optoelectronics.     

氧化镍/膨胀石墨复合物的合成及其电容性能

采用液相沉淀法制备了膨胀石墨(EG)质量分数为40%的氧化镍/膨胀石墨(NiO/EG)复合物,研究了该复合物电化学性能。结果表明:纳米NiO均匀分散在EG表面;导电性良好的EG显著提高了NiO的电化学性能。在6 mol.L–1 KOH电解液中,NiO/EG复合物电极的氧化和还原峰的电位差降低了0.141 V,100 mA.g–1电流密度下比容量可达到370 F.g–1,远高于纯NiO(约206 F.g–1)和纯EG的比容量(约25 F.g–1)。NiO/EG复合物在充放电500次后,比容量仅衰减了2.5%。     

基于沉淀转化法制备的纳米NiO超级电容器研究

运用沉淀转化法制备Ni(OH)2超微粉末,并通过热处理得到纳米NiO。利用TG、XRD、TEM、N2吸附、循环伏安和恒流充放电测试对样品进行了分析和表征。结果表明,实验制备的NiO粒径为10nm左右,比表面积达到186.3m2/g,并具有合适的孔径分布,NiO赝电容器的工作电压为0.35V,在电流密度为60mA/g时,其比容达到243F/g。     

Effect of warpage on the electronic structure and optical properties of bilayer germanene

The electronic structure and optical properties of bilayer germanene under different warpages are studied by the first-principles method of density functional theory. The effects of warpages on the electronic structure and optical properties of bilayer germanene are analyzed. The results of the electronic structure study show that the bottom of the conduction band of bilayer germanene moves to the lower energy direction with the increase of warpages at the K point, and the top of the valence band stays constant at the K point, and so the band gap decreases with the increase of warpage. When the warpage is 0.075 nm, the top of the valence band of bilayer germanene changes from K point to G point, and the bilayer germanene becomes an indirect band gap semiconductor. This is an effective means to modulate the conversion of bilayer germanene between direct band gap semiconductor and indirect band gap semiconductor by adjusting the band structure of bilayer germanene effectively. The study of optical properties shows that the effect of warpage on the optical properties of bilayer germanene is mainly distributed in the ultraviolet and visible regions, and the warpage can effectively regulate the electronic structure and optical properties of bilayer germanene. When the warpage is 0.069 nm, the first peak of dielectric function and extinction coefficient is the largest, and the energy corresponding to the absorption band edge is the smallest. Therefore, the electron utilization rate is the best when the warpage is 0.069 nm.     

High performance electric field micro sensor with combined differential structure

This paper presents a high performance electric field micro sensor with combined differential structure. The sensor consists of two backward laid micro-machined chips, each packaged by polymer and metal. The novel combined differential structure effectively reduces various environmental affections, such as thermal drift, humidity drift and electrostatic charge accumulation. The sensor is tested in near-ground place as well as balloon-borne sounding. In different weather conditions, the measureinent results showed good agreement with those of the commercial electric field mill.     

Influences of structure around gate-edge on high electric field strength in MISFETs with high-k gate dielectrics

In this paper, dependences of electric field strength around gate-edge in gate dielectrics of MISFETs with high-k gate dielectrics on design parameters are studied. It is newly found that locations of sidewall/gate dielectric interfaces relative to gate electrode edges are critical to electric field strength of high-k MISFETs. Electric field can be as high as 4 MV/cm, which could have large influences on the yield of large scale integrated circuits (LSIs) with high-k gate dielectrics. An explanation of this phenomenon is given by considering discontinuity in electric field at interfaces between two materials with different dielectric constants. It is clarified that an electrical potential of side and top surfaces of gate dielectrics is strongly affected by the discontinuity of electric field strength at interfaces. As a result, electric field strength around gate electrode edges critically depends on locations of sidewall/gate dielectrics interfaces relative to gate electrode edges. Based on the physical considerations, a structure, in which gate sidewalls are also made of high-k materials, is studied from the viewpoint of electric field strength around gate electrode edges. It is shown that this structure effectively suppresses electric field strength around gate edges.     

浅议工程领域电子技术的应用

随着社会的飞速发展,近年来我国电子技术取得了较大进步,电子技术在工程领域的应用得到广泛运用,给我国人民的生活带来了巨大的变化,为我国工程的经济发展做出了重要贡献。但是与国外相比,工程领域电子技术在我国发展时间并不长,电子技术在工程领域应用有着巨大的潜力。     

NiO薄膜的脉冲激光沉积及其结构和光学特性研究

利用脉冲激光沉积法在ITO玻璃衬底上制备了NiO薄膜,利用XRD、AFM对样品的晶体结构和表面形貌进行了表征,并对其透射光谱进行了测试,研究了衬底温度及脉冲激光能量对所制NiO薄膜的结构、形貌和光学特性的影响。结果表明:在脉冲激光能量为180 mJ、衬底温度为600~700℃条件下所制备的样品为沿(111)晶面择优取向生长的多晶NiO薄膜,薄膜结晶质量良好,表面颗粒排列均匀,可见光透射率较高,禁带宽度为3.40~3.47 eV。     

Si/NiO异质pn结的光电性能研究

利用磁控溅射方法成功制备了Si/NiO异质pn结。实 验表明,退火温度升到400℃时,Si/NiO异 质结呈现一定的整流特性;600℃退火的Si/NiO异质结呈现很好的整 流特性,正向开启 电压达到3.5VV时出现漏电流。这可 能是因为600℃退火后,样品结晶转好,应力 释放,缺陷减少,从而改善了样品的整流特性。这一结果得到了X射线衍射(XRD)、原子显微 镜(AFM)和紫外(UV)结果的充分支持。