Mn掺杂对SrBiFeO陶瓷NTC特性的影响

以Bi2O3,Fe2O3,MnO2和SrCO3为主要原料,采用传统固相法制备出具有负温度系数(NTC)特性的SrBiFeMnO陶瓷。研究了该陶瓷的物相结构、断面形貌及电性能。结果表明:试样的室温电阻率ρ25和热敏电阻特性常数B25/85随着x(Mn)的增加均呈现先增大后减小的趋势。在25～200℃的测试温区内,x(Mn)为0.1时,掺杂的SrBiFeO陶瓷材料的电阻率-温度特性呈现良好的线性关系;x(Mn)为0.5时,掺杂SrBiFeO陶瓷材料具有较好的NTC特性,其ρ25为145Ω.cm,B25/85为2950K。     

Ni掺杂量对BaBiO_3基热敏陶瓷电性能的影响

通过X线衍射(XRD)、扫描电子显微镜(SEM)和阻温特性测试仪,研究了不同NiO、Ni_2O_3掺杂量对BaNi~Ⅱ_xBi_(1-x)O_3和BaNi~Ⅱ_(x/3)Ni~Ⅲ_(2x/3)Bi_(1-x)O_3(摩尔比x=0.02~0.08)热敏陶瓷的物相、显微结构及电性能的影响。结果表明,BaNi~Ⅱ_xBi_(1-x)O_3与BaNi~Ⅱ_(x/3)Ni~Ⅲ_(2x/3)Bi_(1-x)O_3热敏陶瓷的室温电阻率ρ25及热敏常数B25~85值均随着NiO/Ni_2O_3掺杂量的增加呈现先减小后变大的趋势;试样BaNi~Ⅱ_(0.04)Bi_(0.96)O_3取得了良好的热敏性能,ρ25=2 743Ω·cm,B25~85=3 239K;BaNi~Ⅱ_(0.02)Ni~Ⅲ_(0.04)Bi_(0.94)O_3陶瓷的ρ25和B25~85的最优值分别为65Ω·cm和2 673K。     

Nb掺杂量对SrBiFeO基陶瓷NTC特性的影响

采用传统固相法,按化学式Sr0.65Bi1-xFe0.35NbxO3(x=0.01,0.02,0.05,0.10和0.20)制备了具有NTC特性的Nb掺杂SrBiFeO基陶瓷试样。研究了Nb掺杂量对其NTC特性的影响。结果表明:试样的ρ25和B25/85值随着Nb含量的增加都呈现增加趋势;在25~200℃的测试温区内,其电阻率–温度特性呈现近似的线性关系;当x为0.05时,线性关系较好,其中ρ25的值约为6700?·cm,B25/85值约为3540K。     

退火温度对Mn-Co-Ni-O系NTC薄膜阻温特性的影响

采用传统陶瓷工艺制作溅射靶材,通过射频磁控溅射法在Al2O3基片上制备了Mn-Co-Ni-O系NTC薄膜。利用X射线衍射仪(XRD)、原子力显微镜(AFM)对不同退火温度下制备的NTC薄膜的结构和形貌进行表征。经过蒸发电极、内电极图形化、淀积二氧化硅钝化层等工艺,将薄膜制成0805规格NTC热敏电阻器。利用高低温试验箱等测试系统对其性能进行测试,研究了退火温度对薄膜阻温特性的影响。结果表明,随着退火温度的升高,晶粒逐渐长大,当退火温度为950℃时,晶粒大小均匀,成相平整致密;材料常数B随着退火温度的升高而增大。     

Cu掺杂n型硅材料的制备及热敏特性研究

通过高温扩散的方法制备出铜掺杂的n型单晶硅材料,详细研究了不同制备条件所得材料的电学及热敏特性。结果表明当铜表面源浓度为1.83×10-7mol/cm2时,1200℃下扩散2个小时得到的铜掺杂补偿硅材料的电阻率达到最大值46.2Ω?cm。测试表明铜掺杂n型单晶硅材料具有良好的负温度系数热敏特性,B值分布于3010K-4130K之间。     

高质量Mg掺杂的P型Al0.2Ga0.8N的生长和电学特性研究

The growth of high-performance Mg-doped p-type AlxGa1-xN （x = 0.2） using metal-organic chemical vapor deposition is reported. The influence of growth conditions （growth temperature, magnesium flow, and thermal annealing temperature） on the electrical properties of Mg-doped ptype AlxGa1-xN （x = 0.2） has been investigated. Using the optimized conditions, we obtained a minimum p-type resistivity of 0.71 Ω·cm for p-type AlGaN with 20% Al fraction.     

激光照射对p型碲镉汞的结构、电学和光学特性的影响

用不同能量密度的激光脉冲照射布里奇曼法生长的块状p型的Hg_(1-x)Cd_xTe(x=0.16)单晶。应用能产生0.53μm波长的10ns脉冲(倍频)和能量密度可变(2～50mJ/cm~2)的脉冲激光器(Nd:YAG),在77～300K温度范围内,对原生的及激光照射的单晶样品,用范德堡法进行直流电导率及霍耳系数测量,还在室温下对样品进行X射线衍射图样及透射测量。电学研究表明,p型碲镉汞在激光照射后变成了n型;光学研究结构表明,激光照射后,自由载流子浓度陡增,透射微乎其微;X射线研究表明,p型单晶样品受激光照射后,结构也发生了变化,在晶格中引入了CdTe、Hg和Te相。     

NTC and electrical properties of nickel and gold doped n-type silicon material

iconductor deep level energy are basically consistent with the experimental results.     

一种新型NTC厚膜电阻的制备及电性能研究

以新型BaCoⅡ 0.05CoⅢ0.1Bi0.85O3材料为基体,以CuO为烧结助剂,在790、800、810℃烧结4h制备了NTC厚膜电阻。借助XRD、SEM和阻温特性测试仪,研究了CuO含量对电阻相组成、微观结构及电性能的影响。结果表明:烧结温度为800℃的NTC厚膜电阻主要物相为具有复合立方钙钛矿结构的BaCoⅡ0.05CoⅢ0.1Bi0.85O3,并有少量Bi2O3剩余;该组电阻表面颗粒均匀细小,致密性随CuO含量的增加而趋于增加。对烧结温度为790℃的电阻来说,其室温电阻R25和B25/85随CuO含量的增加而逐渐降低;该电阻的R25、B25/85及活化能Ea分别为0.98~13.40kΩ、931~1855K和0.08~0.16eV。     

Electrical properties of nickel in silicon

Electrical activity and energy levels as well as diffusion properties of nickel in silicon have not yet been reliably established. In this paper, we investigated the diffusion and the electrical properties of nickel in silicon to confirm that nickel is electrically active and introduces one acceptor and one donor level by combined measurements of Hall coefficient and DLTS, and measurements of the distribution of electrically active nickel in various silicon diodes by DLTS. The former experiments show that bothn- andp- type silicon are compensated by nickel and that nickel introduces an acceptor level ofE _c-0.47 ± 0.04 eV and a donor level ofE _v +0.18 ± 0.02 eV. The concentrations of these two levels are almost identical over the diffusion temperatures from about 800 to 1100° C, indicating that these donor and acceptor levels are due to different charge states of the same nickel center. In the distribution measurements of electrically active nickel in silicon diodes, we inspected how nickel can be observed by DLTS. It was found that the nickel diffusion intop- n junction is rather complicated, the distribution profiles of nickel in the vicinity of thep- n junction being markedly influenced by an additional heating at elevated temperatures after the nickel diffusion. This gives evidence that the difference in silicon devices used in various studies could give rise to different results.     

Zn掺杂对Ni-Mn-Cu-O系NTC热敏电阻的影响

采用传统固相反应法制备了Zn掺杂的Ni0.5Mn2.38–x Cu0.12Znx O4(x=0,0.2,0.4,0.6,0.8)系列MF58型NTC热敏电阻工业化产品,使用XRD、SEM、XPS等技术手段表征了所制陶瓷烧结体的晶体结构、微观结构和成分,重点考察了Zn元素含量对热敏电阻电学性能和老化值的影响。结果表明:随着Zn含量的增加,Ni0.5Mn2.38–x Cu0.12Znx O4固溶体的晶体结构从立方尖晶石转变成四方尖晶石,样品的电阻率和热敏常数B值呈现逐步增加的趋势,同时老化值显著减小,当x=0.8时,其在150℃放置6天后的老化值可低至0.33%。     

降温速率对Mn-Ni-Fe-O系热敏陶瓷电学性能的影响

采用草酸盐共沉淀法制备了Mn-Ni-Fe-O体系NTC(Negative Temperature Coefficient)热敏陶瓷,并运用XRD,SEM和电学性能测试等手段研究陶瓷样品的相结构和电学性能,重点考察了降温速率对电学性能的影响。结果表明：慢速降温条件下样品的电阻率低于快速降温的电阻率,降温速率对Mn-Ni-...     

La_2O_3掺杂对Mn-Co-Ni系NTC热敏电阻材料性能的影响

采用传统陶瓷工艺制备了Mn1.6Co0.8Ni0.6O4–xLa2O3(x=0,0.01,0.03,0.05,0.07)系列NTC热敏电阻样品,运用XRD、SEM和电性能测试等手段,研究了La2O3掺杂对样品相结构和电性能的影响。结果表明:所制掺杂样品均由尖晶石相和钙钛矿相组成,其中钙钛矿相的名义组成可用化学式La(Mn-Co-Ni)O3表示,随着La2O3掺杂量x由0增加到0.07,Mn-Co-Ni系NTC热敏电阻材料的电阻率由643.cm增加到912.cm,相反地材料常数B值却由3 464 K减小到3 393 K。     

SrBiFeO基NTC陶瓷的制备及其电性能研究

以Bi2O3、Fe2O3和SrCO3为主要原料,采用传统固相法制备出具有NTC特性的SrBiFeO(SBF)陶瓷。研究了该陶瓷的物相结构、断面形貌及电性能。结果表明:试样由BiFeO3、SrFeO3-x和三方晶系的Sr2.25Bi6.75O12.38相组成,试样的室温电阻率ρ25随Fe2O3掺杂量的增加呈现先减小后增大的趋势,而B25/85值却呈现单调递增趋势,陶瓷试样SBF30即:n(Bi2O3):n(SrCO3):n(Fe2O3)=50:70:15时具有较好的NTC特性,ρ25为1.192×103Ω.cm,B25/85值为3 604 K。     

Characterization of near-surface electrical properties of multi-crystalline silicon wafers

This experiment is concerned with photoconductive decay (PCD) measurements devised specifically for the purpose of characterization of the near-surface region of semiconductor substrates. Specifically, the method is utilized to evaluate the effects of crystallographic orientation, grain boundaries, and surface texturing on the near-surface electrical properties of multi-crystalline silicon (mc-Si) wafers used for solar cell applications. The PCD method is also explored for the purposes of monitoring processes used in the manufacture of mc-Si solar cells. The effect of saw damage and damage removal by wet etching on the near-surface lifetime of minority carriers and carrier mobility in mc-Si wafers is quantitatively determined. The results obtained demonstrate a direct correlation between condition of the mc-Si surface and the electrical parameters measured. It is postulated that the PCD method using temporary contact can be effectively used to monitor the condition of mc-Si surfaces during solar cell manufacturing.     

选择镀镍金中镀金面积与厚度关系的研究与改善

随着现代电子技术的不断发展,电路板中将有越来越多的镀镍金表面工艺,来满足开关、触点及耐摩擦等方面的要求。图形的分布不均给电路板镀镍金的表面处理带来了诸如金厚度、金表观等难以克服的缺陷。从电镀的原理方面入手,分析造成这些缺陷的原因,并给出相应的解决办法,为以后选择镀镍金为表面处理方式的产品的加工提供一种新的思路与方法。