共查询到18条相似文献，搜索用时 46 毫秒
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从自旋扩散方程和欧姆定律出发研究了铁磁层到有机半导体的自旋注入,得到了系统的电流自旋极化率。有机半导体中的载流子为自旋极化子和不带自旋的双极化子,极化子比率在有机半导体内随输运距离变化。通过计算发现匹配的铁磁和有机半导体电导率有利于自旋注入;通过调节界面电阻自旋相关性,电流自旋极化率可获得很大程度提高;极化子比率衰减速率对有机半导体电流自旋极化率具有非常重要的影响。 相似文献
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根据有机半导体中的电流自旋极化注入和输运实验现象,理论上研究了铁磁/有机半导体/铁磁系统的电流自旋极化性质.考虑到有机半导体的具体特性,从自旋扩散理论和欧姆定律出发,得到了系统的电流自旋极化率.假设自旋极化子和不带自旋的双极化子为有机半导体中的载流子.通过计算发现,极化子为实现有机半导体中电流极化注入和输运的有效自旋载流子,即使它只占总载流子很少一部分.还进一步研究了自旋相关界面电阻和电导率匹配以及有机半导体长度等因素对系统电流自旋极化的影响.关键词：自旋电子学自旋注入有机半导体极化子 相似文献
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磁台阶势垒结构中二维电子气的自旋极化输运 总被引：1，自引：0，他引：1
运用散射矩阵方法,研究了台阶磁势垒量子结构中二维电子气的隧穿输运性质.结果表明：在零偏压下,电子传输概率的自旋极化曲线随入射能量的增加而振荡衰减;随着磁台阶数的增加,电子传输概率的自旋极化度最大值减小,同时电子传输概率的自旋极化度振荡衰减也越来越慢;随着磁台阶的总宽度增加,电子传输概率的自旋极化曲线出现更明显的振荡,电子隧穿磁台阶势垒表现出明显的量子尺寸效应;在偏置电压的作用下,电子传输概率的自旋极化度在宽广的入射能量区出现明显的振荡增大,电子隧穿磁台阶势垒表现出更明显的自旋过滤效应.关键词：磁台阶势垒自旋极化自旋过滤 相似文献
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文中用一维紧束缚模型描述铁磁金属,用一维非简并的Su-Schrieffer -Heeger (SSH)模型描述共轭聚合物,研究了在一维铁磁/共轭聚合物系统和一维CMR材料/ 聚合物系统中的电子转移和自旋转移.发现在聚合物部分没有自旋的双极化子比有自旋的极化子具有较低的能量而容易产生.然而在铁磁CMR材料/聚合物系统中极化子的产生能低于聚合物中极化子的产生能,增加了有机物中自旋极化输运的可能性. 相似文献
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在77到292K的范围内,系统研究了含InAs自组装量子点的金属-半导体-金属双肖特基势垒二极管的输运特性.随着温度上升,量子点的存储效应引起的电流回路逐渐减小.在测试温度范围内,通过量子点的共振隧穿过程在电流电压(I-V)曲线中造成台阶结构,且使电流回路随温度的上升急剧减小.根据肖特基势垒的反向I-V曲线,计算了势垒的反向饱和电流密度和平均理想因子.发现共振随穿效应使肖特基势垒在更大的程度上偏离了理想情况,而量子点的电子存储效应主要改变了肖特基势垒的有效势垒高度,从而影响了势垒的反向饱和电流密度关键词：自组装量子点肖特基势垒电流-电压特性 相似文献
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GaN基肖特基势垒二极管结构优化研究进展 总被引：2，自引：1，他引：1
作为宽禁带半导体器件'GaN基肖特基势垒二极管（SBD）有耐高压、耐高温、导通电阻小等优良特性'这使得它在电力电子等领域有广泛应用。本文首先综述了SBD发展要解决的问题;然后'介绍了GaNSBD结构、工作原理及结构优化研究进展;接下来'总结了AlGaN/GaNSBD结构、工作原理及结构优化研究进展'并着重从AlGaN/GaNSBD的外延片结构、肖特基电极结构以及边缘终端结构等角度'阐述了这些结构的优化对AlGaN/GaNSBD性能的影响;最后'对器件进一步的发展方向进行了展望。
相似文献11.
The effects of electric and magnetic fields on the current spin polarization and magnetoresistance in a ferromagnetic/organic semiconductor/ferromagnetic（FM/OSC/FM） system 
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下载免费PDF全文 From experimental results of spin polarized injection and transport in organic semiconductors(OSCs),we theoretically study the current spin polarization and magnetoresistance under an electric and a magnetic field in a ferromagnetic/organic semiconductor/ferromagnetic(FM/OSC/FM) sandwich structure according to the spin drift-diffusion theory and Ohm’s law.From the calculations,it is found that the interfacial current spin polarization is enhanced by several orders of magnitude through tuning the magnetic and electric fields by taking into account the specific characteristics of OSC.Furthermore,the effects of the electric and magnetic fields on the magnetoresistance are also discussed in the sandwich structure. 相似文献
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Fundamentals of the Schottky contacts and thehigh-temperature current conduction through three kinds of Schottkydiodes are studied. N-Si Schottky diodes, GaN Schottky diodes andAlGaN/GaN Schottky diodes are investigated by I--V--Tmeasurements ranging from 300 to 523~K. For these Schottky diodes, arise in temperature is accompanied with an increase in barrierheight and a reduction in ideality factor. Mechanisms aresuggested, including thermionic emission, field emission,trap-assisted tunnelling and so on. The most remarkable finding inthe present paper is that these three kinds of Schottky diodes arerevealed to have different behaviours of high-temperature reversecurrents. For the n-Si Schottky diode, a rise in temperature isaccompanied by an increase in reverse current. The reverse currentof the GaN Schottky diode decreases first and then increases withrising temperature. The AlGaN/GaN Schottky diode has a trendopposite to that of the GaN Schottky diode, and the dominantmechanisms are the effects of the piezoelectric polarization field andvariation of two-dimensional electron gas charge density. 相似文献
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We report on the temperature-dependent Schottky barrier in organic solar cells based on PTB7:PC71BM. The ideality factor is found to increase with temperature decreasing, which is explained by a model in which the solar cell is taken as Schottky barrier diode. Accordingly, the dark current in the device originates from the thermally emitted electrons across the Schottky barrier. The fittings obtained with the thermal emission theory are systematically studied at different temperatures. It is concluded that the blend/Ca/Al interface presents great inhomogeneity, which can be described by 2 sets of Gaussian distributions with large zero bias standard deviations. With the decrease of temperature, electrons favor going across the Schottky barrier patches with lower barrier height and as a consequence the ideally factor significantly increases at low temperature. 相似文献
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With the help of broadband dielectric spectroscopy in a wide temperature and frequency range, the conductivity spectra of ZnO polycrystalline ceramics are measured and the direct-current-like (DC-like) conductivity and relaxation polarization conductivity are observed successively along the frequency axis. According to the classical Debye theory and Cole-Cole equation, the physical meanings of the two conductivities are discussed. It is found that the DC-like conductivity corresponds to electron transportation over the Schottky barrier at the grainboundary. The relaxation polarization conductivity corresponds to electronic trap relaxation of intrinsic point defects (zinc interstitial and oxygen vacancy). When in the high frequency region, the relaxation conductivity obeys the universal law with the index n equal to the index α in the Cole-Cole equation as an indictor of disorder degree. 相似文献
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K. Sarpatwari S. E. Mohney S. Ashok O. O. Awadelkarim 《physica status solidi (a)》2010,207(6):1509-1513
Current–voltage–temperature, capacitance–voltage, and Fourier transform‐deep level transient spectroscopy (FT‐DLTS) measurements have been employed to gain insights into the conduction mechanism in Re/4H n‐silicon carbide (SiC) Schottky diodes. A power law dependence of current on voltage has been observed in the Re/4H‐SiC Schottky diodes at large forward bias. DLTS studies of the diodes reveal the presence of a deep trap at an energy . The electron trap center is tentatively associated with the prominent Z1 defect level, and the obtained trap density and capture cross‐section values correlate well with available literature values. Excess capacitance has been observed under forward bias suggesting that minority carrier injection is the mechanism responsible for the observed characteristics. 相似文献
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