(Sr,Co,Nb）掺杂SnO2压敏电阻的电学非线性

研究了Sr对新型(Co, Nb)掺杂SnO₂压敏材料微观结构和电学性质的影响.当SrCO ₃的含量从零增加到1.50mol%时，(Co, Nb)掺杂SnO₂压敏电阻的击穿电压从240V/mm猛增 到1482V/mm.样品的微观结构分析发现, 当SrCO₃的含量从零增加到1.50 mol%时, SnO2的晶粒尺寸迅速减小．晶界势垒高度测量揭示，SnO₂晶粒尺寸的迅速减小是击穿 关键词： 碳酸锶 二氧化锡 势垒 电学非线性     

铁磁/半导体/铁磁结构的双量子环自旋输运的特性

研究了与铁磁/半导体/铁磁结构相关的双量子环自旋输运的规律,研究结果表明：总磁通为零条件下,铁磁电极磁化方向反平行时,双量子环与单量子环相比提高了自旋电子透射概率的平均值.铁磁电极磁化方向平行时,双量子环对提高自旋向下电子平均透射概率的效果更明显;双量子环受到Rashba自旋轨道耦合作用影响时,自旋电子的平均透射概率明显高于单量子环,即使再加上外加磁场的影响,透射概率较高这一特征依然存在;双量子环所含的δ势垒具有阻碍自旋电子输运的作用,随δ势垒强度Z的增大透射概率 关键词： 双量子环 Rashba自旋轨道耦合 透射概率 δ势垒')" href="#">δ势垒     

InAs量子点在肖特基势垒二极管输运特性中的影响

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     

半导体器件蒙特卡罗模拟中保持电荷守恒的统计增强方法

介绍了一种在半导体器件蒙特卡罗模拟中保持电荷守恒的统计增强方法,该方法消除了由统计增强引入的电荷统计涨落,保持了不同增强区界面处过界粒子流的连续性.以肖特基势垒二极管为例,应用该方法,实现了高接触势垒情形下的正反向电流模拟.     

阻挡杂质带红外探测器中的界面势垒效应

通过变温暗电流和变偏压光电流谱实验对阻挡杂质带红外探测器的跃迁机理和输运特性进行了研究. 结合器件能带结构计算的结果, 证明了在阻挡杂质带红外探测器中主要由导带底下移效应引起的界面势垒的存在. 提出了阻挡杂质带红外探测器的双激发工作模型, 并从变偏压光电流谱中成功地分离出了与这两种物理过程所对应的光谱峰, 进一步证实了器件的能带结构. 研究了界面势垒效应对阻挡杂质带红外探测器的光电流谱、响应率和内量子效率的影响. 研究表明, 考虑进界面势垒效应, 计算得到的器件响应率与实验值符合得很好. 同时发现阻挡杂质带红外探测器中内建电场的存在等效降低了发生碰撞电离增益所需的临界电场强度.     

High-temperature current conduction through three kinds of Schottky diodes

Fundamentals of the Schottky contacts and the high-temperature current conduction through three kinds of Schottky diodes are studied. N-Si Schottky diodes, GaN Schottky diodes and AlGaN/GaN Schottky diodes are investigated by I--V--T measurements ranging from 300 to 523~K. For these Schottky diodes, a rise in temperature is accompanied with an increase in barrier height and a reduction in ideality factor. Mechanisms are suggested, including thermionic emission, field emission, trap-assisted tunnelling and so on. The most remarkable finding in the present paper is that these three kinds of Schottky diodes are revealed to have different behaviours of high-temperature reverse currents. For the n-Si Schottky diode, a rise in temperature is accompanied by an increase in reverse current. The reverse current of the GaN Schottky diode decreases first and then increases with rising temperature. The AlGaN/GaN Schottky diode has a trend opposite to that of the GaN Schottky diode, and the dominant mechanisms are the effects of the piezoelectric polarization field and variation of two-dimensional electron gas charge density.     

Electrical Characteristics of Co/n-Si Schottky Barrier Diodes Using I-V and C-V Measurements

Electrical characteristics of Co/n-Si Schottky barrier diodes are analysed by current- voltage （I- V） and capacitancevoltage （C- V） techniques at room temperature. The electronic parameters such as ideality factor, barrier height and average series resistance are determined. The barrier height 0. 76 eV obtained from the C - V measurements is higher than that of the value 0. 70 eV obtained from the I - V measurements. The series resistance Rs and the ideality factor n are determined from the d ln（ I） /dV plot and are found to be 193.62 Ω and 1.34, respectively. The barrier height and the Rs value are calculated from the H（I） - I plot and are found to be 0.71 eV and 205.95Ω. Furthermore, the energy distribution of the interface state density is determined from the forward bias I - V characteristics by taking into account the bias dependence of the effective barrier height. The interface state density Nss ranges from 6.484×10^11 cm^-2eV^-1 in （Ec - 0.446） eV to 2.801×10^10 cm^-2eV^-1 in （Ec - 0.631） eV, of the Co/n-Si Schottky barrier diode. The results show the presence of a thin interracial layer between the metal and the semiconductor.     

若干In2Se3 化合物的晶体结构与电子特性

等离激元是金属中自由电子的集体振荡,其在物理,生物、化学、能源、信息等领域具有重要的应用前景。近些年来对等离激元量子效应研究的深入开展使得等离激元研究迈入了新阶段。本文首先简要介绍了等离激元的两个基本特性：光压缩效应和局域电场增强效应;随后回顾了量子等离激元方面的最新的进展,包括量子纠缠效应,量子尺寸效应,量子遂穿效应,等离激元在台阶势垒处的反射与激发,等离激元对电子相干效应的增强;最后对量子等离激元研究进行了总结和展望。     

Mechanism of improving forward and reverse blocking voltages in AlGaN/GaN HEMTs by using Schottky drain

In this paper, we demonstrate that a Schottky drain can improve the forward and reverse blocking voltages(BVs)simultaneously in AlGaN/GaN high-electron mobility transistors(HEMTs). The mechanism of improving the two BVs is investigated by analysing the leakage current components and by software simulation. The forward BV increases from72 V to 149 V due to the good Schottky contact morphology. During the reverse bias, the buffer leakage in the Ohmicdrain HEMT increases significantly with the increase of the negative drain bias. For the Schottky-drain HEMT, the buffer leakage is suppressed effectively by the formation of the depletion region at the drain terminal. As a result, the reverse BV is enhanced from-5 V to-49 V by using a Schottky drain. Experiments and the simulation indicate that a Schottky drain is desirable for power electronic applications.     

GaN光电阴极表面势垒对电子逸出几率的影响

针对GaN光电阴极表面势垒对电子逸出几率的影响问题,应用玻尓兹曼分布和基于Airy函数的传递矩阵法计算了GaN光电阴极的电子逸出几率,发现电子逸出几率主要由I势垒决定,II势垒对电子逸出几率的影响有限.利用自行研制的GaN光电阴极激活评估实验系统,测试了透射式GaN光电阴极样品的激活光电流.实验发现,Cs单独激活引起电子逸出几率的显著增加,而Cs单独充分激活后的Cs/O交替激活对电子逸出几率的影响有限.理论计算结果与激活光电流测试结果一致,其原因是Cs单独激活对降低真空能级的贡献远大于Cs/O共同激活.