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碱金属掺杂的铁系陶瓷湿敏材料特性研究 总被引:3,自引:0,他引:3
本文报导了碱金属掺杂对以 Fe_2O_3为基的陶瓷材料湿敏特性影响的研究结果。碱金属掺杂对改善材料敏感性与微组织结构有显著作用。研究发现,K~+,La~(3+)等离子的掺杂能明显降低材料固有阻值,提高低湿区敏感特性,改善阻—湿特性的线性关系。文中对水法处理与多元掺杂对减小材料湿滞,提高感湿灵敏度的作用机制给予了讨论。 相似文献
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采用基于密度泛函理论(DFT)的第一性原理平面波超软赝势方法计算了Li、Na、K掺杂ZnO纤锌矿结构的晶格结构、电子结构(能带结构、态密度)和光学特性,计算结果表明,在掺杂Na或K的情况下,晶胞体积的计算值均略有增加,而掺杂Li的晶胞体积小于本征ZnO,原因可能是系统能量的减小导致晶胞体积的降低。Li、Na掺杂的ZnO形成了p型导电半导体而K掺杂并未改变ZnO的导电类型,同时,综合电荷分布结果可以看出,Li掺ZnO具有相对较好的p型导电性能。此外,Li、Na、K掺杂ZnO后,吸收率在可见光区出现了明显的增大,其中Li掺ZnO在380 nm附近出现了较强的吸收峰,这对ZnO在光电子器件上的应用具有一定的参考价值。 相似文献
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本文报告了 LPCVD 制备的掺硼硅薄膜结构和物理性质分析,发现掺杂比 R 在1×10~(-5)—4×10~(-2)的范围内,材料可划分为三种不同的相结构区:非晶态硅(a-Si)、非晶态硅-硼合金(a-Si∶B)和非晶态微晶硅(μc-Si)。物理性质测量也发现三种不同的结构区具有不同的特性和氢化规律。在 a-Si∶B 区,霍尔系数符号是空穴导电的正号,而μc-Si 区材料进入简并状态。氢化明显地改善了材料的物理性质和掺杂效率,但对于重掺杂微晶区材料,氢化似乎使掺杂效率降低。 相似文献
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本文报告了LPCVD 制备的掺硼硅薄膜结构和物理性质分析,发现掺杂比R 在1×10~(-5)—4×10~(-2)的范围内,材料可划分为三种不同的相结构区:非晶态硅(a-Si)、非晶态硅-硼合金(a-Si∶B)和非晶态微晶硅(μc-Si)。物理性质测量也发现三种不同的结构区具有不同的特性和氢化规律。在a-Si∶B 区,霍尔系数符号是空穴导电的正号,而μc-Si 区材料进入简并状态。氢化明显地改善了材料的物理性质和掺杂效率,但对于重掺杂微晶区材料,氢化似乎使掺杂效率降低。 相似文献
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碳纳米管场效应晶体管电子输运性质是其结构参量(纵向结构参量:如CNT的直径、栅介质层厚度、介质介电常数等;横向结构参量:如沟道长度、源/漏区掺杂浓度等)的复杂函数.本论文在量子力学非平衡格林函数理论框架内,通过自洽求解泊松方程和薛定谔方程以得到MOS-CNTFET电子输运特性.在此基础上系统地研究了沟道长度及源/漏区掺杂浓度对MOS-CNTFET器件的漏极导通电流、关态泄漏电流、开关态电流比、阈值电压、亚阈值摆幅及双极性传导等输运性质的影响.结果表明:当沟道长度在15 nm以上时,上述各性质受沟道长度的影响均较小,而导通电流、开关态电流比及双极性传导特性与源/漏掺杂浓度的大小有关,开关态电流比与掺杂浓度正相关,导通电流及双极性导电特性与源/漏掺杂浓度负相关.当沟道长度小于15 nm时,随沟道长度减小,漏极导通电流呈增加趋势,但同时导致器件阈值电压及开关电流比减小,关态漏电流及亚阈值摆幅增大且双极性传导现象严重,短沟道效应增强,此时,通过适当降低源/漏掺杂区掺杂浓度,可一定程度地减弱MOS-CNTFET器件短沟道效应. 相似文献
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Yu-Ming Lin Appenzeller J. Knoch J. Avouris P. 《Nanotechnology, IEEE Transactions on》2005,4(5):481-489
State-of-the-art carbon nanotube field-effect transistors (CNFETs) behave as Schottky-barrier-modulated transistors. It is known that vertical scaling of the gate oxide significantly improves the performance of these devices. However, decreasing the oxide thickness also results in pronounced ambipolar transistor characteristics and increased drain leakage currents. Using a novel device concept, we have fabricated high-performance enhancement-mode CNFETs exhibiting n- or p-type unipolar behavior, tunable by electrostatic and/or chemical doping, with excellent OFF-state performance and a steep subthreshold swing (S=63 mV/dec). The device design allows for aggressive oxide thickness and gate-length scaling while maintaining the desired device characteristics. 相似文献
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我们在碘重掺杂聚乙炔(CH)_x基片上,用离子注入法掺钠,形成p~+-(CH)_x/n-(CH)_x结,并测得其电流-电压特性曲线。用P~+区孤子能带中的电子与n区导带底附近的电子,通过结的势垒产生隧道贯穿,形成隧道贯穿电流的模型,导出了结电流随偏置电压和温度变化的关系式,所得结果与实验相符。 相似文献
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Y. Shi C. M. Xiong Y. X. He H. X. Guo X. J. Fan 《Fullerenes, Nanotubes and Carbon Nanostructures》1996,4(5):963-975
N-type doping of the C60 films deposited on Si substrates has been achieved by 80 keV P+-ion implantation with doses of 2×1014 cm-2 at room temperature. The heterostructures composed of the n-type doped C60 films and n- or p-type Si(111), Si(100) substrates are studied in view of semiconductor heterojunctions. The rectification and other electrical characteristics of the P+-ion implanted n-C60/n-(p-)Si heterostructures are disclosed by the current-voltage (I-V) measurements at room temperature. The n-C60/p-Si heterostructures show stronger rectification than n-C60/n-Si heterostructures and Si(111) substrates are found to be more suitable for forming n-C60/Si heterostructures than Si(100) substrates. 相似文献
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A nonenzymatic posttranslational modification of proteins and peptides is the spontaneous deamidation of asparaginyl residues via a succinimide intermediate to form a varying mixture of aspartyl and isoaspartyl residues. The isoaspartyl residue is generally difficult to detect particularly using mass spectrometry because isoaspartic acid is isomeric with aspartic acid so that there is no mass difference. However, electron capture dissociation has demonstrated the ability to differentiate the two isoforms in synthetic peptides using unique diagnostic ions for each form; the cr. + 58 and z(l-r) - 57 fragment ions for the isoAsp form and the Asp side chain loss ((M + nH)(n-1)+. - 60) for the Asp form. Shown here are three examples of isoaspartyl detection in peptides from proteins; a deamidated tryptic peptide of cytochrome c, a tryptic peptide from unfolded and deamidated ribonuclease A, and a tryptic peptide from calmodulin deamidated in its native state. In all cases, the cr. + 58 and z(l-r) - 57 ions allowed the detection and localization of isoaspartyl residues to positions previously occupied by asparaginyl residues. The (M + nH)(n-1)+. - 60 ions were also detected, indicating the presence of aspartyl residues. Observation of these diagnostic ions in peptides from proteins shows that the method is applicable to defining the isomerization state of deamidated proteins. 相似文献
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Technical Physics Letters - A improvement in the operational characteristics of a SiO2-based memristive device is achieved by irradiating its silicon dioxide layer with Xe+ ions, which creates... 相似文献
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Reducing the contact resistance of SiNW devices by employing a heavily doped carrier injection layer
Liu D Shi Z Zhang L He C Zhang J Cheng M Yang R Tian X Bai X Shi D Zhang G 《Nanotechnology》2012,23(30):305701
Silicon nanowires (SiNWs) are promising building blocks for future electronic devices. In SiNW-based devices, reducing the contact resistance of SiNW-metal as much as possible is critically important. Here we report a simple fabrication approach for SiNW field effect transistors (FETs) with low contact resistances by employing a heavily doped carrier injection layer wrapped around SiNWs at the contact region. Both n- and p-type SiNW-FET devices with carrier injection layers were investigated, the contact resistances were one order smaller than those without carrier injection layers and only contribute less than 14.8% for n-type devices and 11.4% for p-type devices, respectively, to the total resistance. Such low contact resistance guarantees the device characteristics mainly from the channel region of SiNW-based devices. 相似文献
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一类神经网络对连续函数的逼近 总被引:1,自引:1,他引:0
借助卷积逼近的工具研究前向神经网络对连续函数的逼近,构造了具有nd个神经元的一类神经网络,并证得用它逼近[0,1]d上的连续函数f(X)时,偏差是O{ω{f,n-d1+2}+n-d1+2‖f‖∞}.其中ω(f,δ)表示f(X)在[0,1]d上的连续模,‖f‖∞表示|f(X)|的极大值. 相似文献
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结合ASHRAE62n-1989和最新的ASHRAE62.1-2007标准,分析高密人群建筑的人员新风量和建筑新风量指标的转变及其特征,并指出我国该类建筑新风量指标合理选择应该重视的问题。 相似文献
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Germanium nanowires grown by chemical vapor deposition exhibit a peculiar dopant incorporation mechanism. The dopant atoms, such as boron and phosphorus, get incorporated through the wire surface, a mechanism which limits the doping modulation along the wire length, and therefore the fabrication of more elaborate structures that combine both n- and p-type doping. Using a novel device design that circumvents these constraints, we demonstrate here a linear Ge nanowire p-n junction. 相似文献
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为给工业制备TinO2n-1多孔电极提供技术支持,以TiH2与TiO2为合成原料,采用高温烧结-压片法制备了TinO2n-1电极。通过扫描电镜(SEM)、X射线衍射仪(XRD)进行材料表征,探究了制备TinO2n-1电极的工艺合理性,利用电化学工作站考察了自制TinO2n-1电极的性能。结果表明:TiH2与TiO2的摩尔比为1∶5,真空下烧结温度为950℃时,可得到主相为Ti4O7的TinO2n-1电极。将自制的亚氧化钛电极与石墨电极分别进行阳极极化测试,亚氧化钛电极析氧电位维持在2.25 V,远高于石墨电极的1.60 V,在循环伏安测试中,TinO2n-1电极表现出很高的电化学稳定性。 相似文献