共查询到19条相似文献,搜索用时 109 毫秒
1.
稀磁半导体--自旋和电荷的桥梁 总被引:5,自引:0,他引:5
稀磁半导体可能同时利用载流子的自旋和电荷自由度构造将磁、电集于一体的半导体器件.尤其是铁磁半导体材料的出现带动了半导体自旋电子学的发展.室温铁磁半导体材料的制备,半导体材料中有效的自旋注入,以及自旋在半导体结构中输运和操作已成为目前半导体自旋电子学领域中的热门课题.稀磁半导体呈现出强烈的自旋相关的光学性质和输运性质,这些效应为人们制备半导体自旋电子学器件提供了物理基础. 相似文献
2.
3.
系统地计算了各种手性碳纳米管最低导带的电子速度和有效质量的变化规律,在此基础上推断手性碳纳米管低偏压下的输运特征,计算表明:在低偏压电子输运时,同一系列(手性角相同)的各种手性金属碳纳米管的输运性质相同,与管径无关,但不同系列的手性金属碳纳米管的输运性质有明显区别;而同一系列的各种手性半导体型碳纳米管的输运性质有一定差异,但不同系列的手性半导体型碳纳米管的输运性质有着显著差异.这一结果说明:碳纳米管在低偏压下的输运特征与系列有着密切的关系,手性角是决定各种碳纳米管在低偏压下具有不同输运性质的最关键的几何参
关键词:
碳纳米管
手性角
电子速度
有效质量 相似文献
4.
5.
大家知道,不含杂质的纯半导体几乎没有什么直接的用途.为了制造半导体器件,人们总是先将半导体材料尽可能地提纯,然后用扩散、离子注入等方法将一定数量的特定杂质掺入半导体的一定部位,以控制半导体的导电类型和电阻率,再经金属蒸发等工艺,最终制成半导体器件.因此,研究杂质的性质和作用是很重要的.在半导体中,有两类性质和作用都绝然不同的杂质:一类杂质是在禁带中引入的能级与导带底或价带顶的能量差很小,远远小于禁带宽度,这类杂质称为浅杂质,它决定着半导体的导电类型与电阻率;另一类杂质在禁带中引入的能级与导带底及价带顶的能量差都… 相似文献
6.
采用第一性原理电子结构和输运性质计算研究了zigzag型单层石墨纳米带(具有armchair 边缘)的电子结构和输运性质及其边缘空位缺陷效应. 研究发现,完整边缘的zigzag型石墨纳米带是具有一定能隙的半导体带,边缘空位缺陷的存在使得纳米带能隙变小,且缺陷浓度越大,能隙越小,并发生了半导体-金属转变. 利用这些研究结果,将有助于在能带工程中实现其电子结构裁剪.
关键词:
石墨纳米带
空位缺陷
电子结构
输运性质 相似文献
7.
半磁半导体是一类新型的半导体材料.本文主要阐述sp-d交换相互作用对半磁半导体(SMSc)中输运特性和杂质行为的影响,讨论了量子输运特性,巨大负磁阻效应,磁场感生的金属─绝缘体转变等一系列新的物理效应以及束缚磁极化子的形成. 相似文献
8.
9.
半导体材料是制造半导体器件的先行,也是开展对半导体的科学研究所必不可少的。制备高纯度的結构完整的半导体材料在半导体学的发展史上起了特別重要的意义。我們知道,极微量的杂貭和缺陷对半导体材料导电性能有决定性的作用,它可以使半导体材料具有适合一定器件的要求的性质,也可使半导体变为毫无用处的废物。半导体材料要求的純度是极高的,对制备晶体管用的锗、硅材料来說,通常要在8个9(純度为 相似文献
10.
11.
The studies of the magnetic and electrical transport properties of ordered magnetic semiconductor nanostructures have been generalized. This new area lies at the intersection of nanotechnologies and fundamental problems of magnetism. The prospects for application of ferromagnetic semiconductors in spintronics have been discussed. A comparative analysis of the magnetic and electrical transport properties of nanowires, thin films, and bulk elemental semiconductors doped with transition metals has been performed. The influence of size effects on the spin dynamics, magnetization, and magnetoresistance of nanostructures has been considered. 相似文献
12.
《中国物理 B》2019,(9)
Magnetic oxide semiconductors are significant spintronics materials.In this article, we review recent advances for homogeneous and inhomogeneous magnetic oxide semiconductors.In the homogeneous magnetic oxide semiconductors,we focus on the various doping techniques including choosing different transition metals, codoping, non-magnetic doping,and even un-doping to realize homogeneous substitution and the clear magnetic origin.And the enhancement of the ferromagnetism is achieved by nanodot arrays engineering, which is accompanied by the tunable optical properties.In the inhomogeneous magnetic oxide semiconductors, we review some heterostructures and their magnetic and transport properties, especially magnetoresistance, which are dramatically modulated by electric field in the constructed devices.And the related mechanisms are discussed in details.Finally, we provide an overview and possible potential applications of magnetic oxide semiconductors. 相似文献
13.
M. A. Idris Z. A. Z. Jamal S. B. Jamaludin N. Nafarizal A. K. Othman M. Z. Sahdan M. P. Zakaria M. Ionescu J. Nowotny 《Ionics》2014,20(4):581-592
The present work considers the application of oxide semiconductors in the conversion of solar energy into the chemical energy required for water purification (removal of microbial cells and toxic organic compounds from water) and the generation of solar hydrogen fuel by photoelectrochemical water splitting. The first part of this work considers the concept of solar energy conversion by oxide semiconductors and the key performance-related properties, including electronic structure, charge transport, flat band potential and surface properties, which are responsible to the reactivity and photoreactivity of oxides with water. The performance of oxide systems for solar energy conversion is briefly considered in terms of an electronic factor. The progress of research in the formation of systems with high performance is considered in terms of specific aspects of nanotechnology, leading to the formation of systems with high performance. The nanotechnology approach in the development of high-performance photocatalysts is considered in terms of the effect of surface energy associated with the formation of nanostructured system on the formation of surface structures that exhibit outstanding properties. The unresolved problems that should be tackled in better understanding of the effect of nanostructures on properties and performance of oxide semiconductors in solar energy conversion are discussed. This part is summarised by a list of unresolved problems of crucial importance in the formation of systems with enhanced performance. This work also formulates the questions that must be addressed in order to overcome the hurdles in the formation of oxide semiconductors with high performance in water purification and the generation of solar fuel. The research strategy in the development of oxide systems with high performance, including photocatalysts for solar water purification and photoelectrodes for photoelectrochemical water splitting, is considered. The considerations are focused on the systems based on titanium dioxide of different defect disorder as well as its solid solutions and composites. 相似文献
14.
Transport properties of doped Bi_2Se_3 and Bi_2Te_3 topological insulators and heterostructures
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this review article, the recent experimental and theoretical research progress in Bi_2Se_3-and Bi_2Te_3-based topological insulators is presented, with a focus on the transport properties and modulation of the transport properties by doping with nonmagnetic and magnetic elements. The electrical transport properties are discussed for a few different types of topological insulator heterostructures, such as heterostructures formed by Bi_2Se_3-and Bi_2Te_3-based binary/ternary/quaternary compounds and superconductors, nonmagnetic and magnetic metals, or semiconductors. 相似文献
15.
We give a brief introduction to the oxide (ZnO, TiO2, In2O3, SnO2, etc.)-based magnetic semiconductors from fundamental material aspects through fascinating magnetic, transport, and optical properties, particularly at room temperature, to promising device applications. The origin of the observed ferromagnetism is also discussed, with a special focus on first-principles investigations of the exchange interactions between transition metal dopants in oxide-based magnetic semiconductors. 相似文献
16.
R. Martins P. Barquinha L. Pereira I. Ferreira E. Fortunato 《Applied Physics A: Materials Science & Processing》2007,89(1):37-42
This paper aims to discuss the effect of order and disorder on the electrical performances of covalent silicon semiconductors
and ZnO based ionic oxide semiconductors used as active channel layers in thin film transistors. The effect of disorder on
covalent semiconductors directly affects their electrical transport properties due to the asymmetric behaviour of sp states,
while in ionic oxide semiconductors it is found that this effect is small due to the fact that angular disorder has no effect
on the spherical symmetry of s states. To this we must add that the mobility of carriers in both systems is quite different,
being also affected by electron–phonon interactions (weak in silicon and strong in ionic oxides leading to formation of polarons).
Besides, the impurity doping effect and the presence of vacancies in disordered silicon and in ionic oxides behave differently,
which will influence the thin film properties and so, the performances of the devices produced.
PACS 81.05.Gc; 81.05.Hd; 85.30.Tv 相似文献
17.
六取代三环喹唑啉电荷传输性质的理论研究 总被引:1,自引:0,他引:1
六取代三环喹唑啉分子可以作为液晶半导体材料。使用电子传输的半经典模型和密度泛函理论方法在B3LYP/6-31G**水平上对六取代三环喹唑啉分子的电荷传输性质进行理论研究。结果显示,该分子的正电荷传输速率为负电荷传输速率的30倍。与苯并菲和六氮杂苯并菲比较,该分子更有利于正电荷传输。 相似文献
18.
By combining the spin dependent transport properties of the ferromagnetic semiconductors with the basic physics of the quantum point contacts, we investigate the spin polarized transport through ferromagnetic semiconductor quantum point contacts. We find that the spin conductance strongly depends on the spin orientation, the magnitude of the spin splitting energy and the shape of the cross sections of the point contacts. 相似文献
19.
Charge transport models developed for disordered organic semiconductors predict a non-Arrhenius temperature dependence ln(mu) proportional, variant1/T(2) for the mobility mu. We demonstrate that in space-charge limited diodes the hole mobility (micro(h)) of a large variety of organic semiconductors shows a universal Arrhenius temperature dependence micro(h)(T) = micro(0)exp(-Delta/kT) at low fields, due to the presence of extrinsic carriers from the Ohmic contact. The transport in a range of organic semiconductors, with a variation in room temperature mobility of more than 6 orders of magnitude, is characterized by a universal mobility micro(0) of 30-40 cm(2)/V s. As a result, we can predict the full temperature dependence of their charge transport properties with only the mobility at one temperature known. 相似文献