共查询到16条相似文献,搜索用时 166 毫秒
1.
采用基于密度泛函理论(DFT)框架下的第一性原理平面波超软赝势方法,在同等环境条件下,建立了不同大小的ZnO模型,在ZnO中对不同浓度的氮和铝原子进行了高掺杂,并对低温条件下高掺杂氮和铝原子的ZnO半导体进行了态密度计算,然后分别对进入价带的相对空穴数和空穴散射迁移率进行了计算,最后对电导率进行了类比,发现适量低浓度的高掺杂氮和铝原子会使ZnO半导体的导电性能增强.即在低温高掺杂氮和铝原子的条件下,ZnO半导体的电导率不仅与掺杂氮和铝原子浓度有关,而且和进入价带的相对空穴数有关.和空穴散射的迁移率有关的结
关键词:
ZnO半导体
浓度
电导率
第一性原理 相似文献
2.
采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法,在相同环境条件下建立了浓度不同的由Ga原子取代Zn原子的Zn1-xGaxO模型.对低温高掺杂Ga原子的Zn1-xGaxO半导体的能带结构、态密度和吸收光谱进行了计算.结果表明:Ga原子浓度越大,进入导带的相对电子数越多,但是电子迁移率反而减小.通过对掺杂和未掺杂ZnO的电导率以及最小间隙带宽度分别进行了比较
关键词:
ZnO高掺杂Ga
电导率
红移
第一性原理 相似文献
3.
基于密度泛函理论框架下的第一性原理平面波超软赝势方法, 构建了未掺杂与相同掺杂浓度的Zn1-xTMxO (TM=Al, Ga, In) 超胞模型,分别对模型进行了几何结构优化、态密度分布和能带分布的计算. 结果表明, 分别高掺杂 (Al, Ga, In) 相同原子分数3.125 at%的条件下, In掺杂对ZnO导电性能最好的结果, 计算结果和实验结果相一致.
关键词:
(Al,Ga,In) 高掺ZnO
导电性能
第一性原理 相似文献
4.
计算了不同Al掺杂浓度下ZnO体系电子结构和光学属性.分析了掺杂对AZO(ZnO:A1)晶体结构、能带、态密度、光学性质的影响.所有计算都是基于密度泛函理论框架下的第一原理平面波赝势方法.计算结果表明:Al掺杂ZnO在导带底引入了大量由掺杂原子贡献的导电载流子,明显提高了体系的电导率.费米能级进入导带.同时,光学性质的计算表明光学带隙明显展宽,且向低能方向漂移;AZO透明导电材料的光学透过率在可见光范围内高达85%,紫外吸收限随着掺杂浓度的增加而发生蓝移.所有计算表明AzO材料可作为优良的透明导电薄膜材料. 相似文献
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目前,虽然In和2N共掺对ZnO导电性能影响的实验研究均有报道,但是,In和2N共掺在ZnO中均是随机掺杂,没有考虑利用ZnO的单极性结构进行择优位向共掺.第一性原理的出现能够解决该问题.因此,本文采用密度泛函理论框架下的第一性原理平面波超软赝势方法,计算了未掺杂ZnO单胞、不同位向高共掺In-2N原子的Zn1-xInxO1-yNy(x=0.0625,y=0.125)两种超胞模型的能带结构分布、态密度分布和吸收光谱分布.计算结果表明,高共掺In-N原子沿c轴取向成键的条件下,掺杂浓度越低,体系更稳定、带隙越窄、有效质量越小、迁移率越增加、相对自由空穴浓度越增加、电导率越增加、导电性能越理想.计算结果与实验结果相一致.这对设计和制备导电功能材料有一定的理论指导作用. 相似文献
7.
采用密度泛函理论框架下的第一性原理平面波超软赝势方法,在相同环境条件下对不同浓度Ge掺杂的In I导电性能进行了研究.建立了由不同浓度的Ge原子替代In原子的In1-x Ge x I(x=0,0.125,0.25)模型.对低温下高掺杂Ge原子的In1-x Ge x I半导体的优化参数、总态密度、能带结构进行了计算.结果表明:Ge的掺入使In1-x Ge x I材料的体积减小,总能量升高,稳定性降低;Ge原子浓度越大,进入导带的相对电子数量越多,In1-x Ge x I电子迁移率减小,电阻率增大,同时最小光学带隙也增大,有利于改善体系的核探测性能. 相似文献
8.
采用第一性原理平面波赝势方法和广义梯度近似计算了ZnO与(Zn,Al)O的电子结构.结合分子轨道理论,从原子布居、键布居、能带结构和态密度角度分析了掺Al前后ZnO的成键情况及对电子间相互作用的影响.利用第一性原理计算结果理论推导计算了(Zn,Al)O的载流子浓度并进一步分析了ZnO电导率的变化情况.与实验结果比较可知,掺Al后ZnO载流子浓度增加,并且ZnO的电导率比未掺杂时有了显著的提高.
关键词:
第一性原理
电子结构
电导率
(Zn
Al)O 相似文献
9.
基于密度泛函理论(DFT)框架下的第一性原理平面波超软赝势方法(USPP),对不同掺杂情况的ZnO晶体几何结构分别进行了优化计算,从理论上给出了ZnO的晶胞参数,得到了ZnO的总体态密度(TDOS)和氮原子2p态的分波态密度(PDOS).计算结果表明:原胞体积随着掺杂比例的提高而逐渐减小;将氮铝按照2∶1的原子比例共掺可以使氮的掺杂浓度比只掺杂氮时明显提高,且随着铝在锌靶中掺入比例的增加,载流子迁移率提高,浓度增大,使得p型ZnO电导率提高,传导特性增强.
关键词:
共掺
p型传导
态密度
第一性原理 相似文献
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Thin films of zinc oxide (ZnO) were deposited on cleaned glass substrates by chemical spray pyrolysis technique using Zn(CH3COO)2 as precursor solution. Also, aluminium-doped thin films of ZnO were prepared by using AlCl3 as doping solution for aluminium. The dopant concentration [Al/Zn atomic percentage (at%)] was varied from 0 to 1.5 at% in
thin films of ZnO prepared in different depositions. Structural characterization of the deposited films was performed with
X-ray diffraction (XRD) studies. It confirmed that all the films were of zinc oxide having polycrystalline nature and possessing
typical hexagonal wurtzite structure with crystallite size varying between 100.7 and 268.6 nm. The films exhibited changes
in relative intensities and crystallite size with changes in the doping concentration of Al. The electrical studies established
that 1 at% of Al-doping was the optimum for enhancing electrical conduction in ZnO thin films and beyond that the distortion
caused in the lattice lowered the conductivity. The films also exhibited distinct changes in their optical properties at different
doping concentrations, including a blue shift and slight widening of bandgap with increasing Al dopant concentration. 相似文献
12.
H/Al共掺杂对ZnO基透明导电薄膜光电性质和晶体结构的影响 总被引:1,自引:0,他引:1
利用H在ZnO中作为浅施主杂质的特性,研究了H掺杂对ZnO:Al透明导电薄膜特性的影响。通过降低ZnO:Al中Al的含量并同时引入H掺杂,解决了透明导电薄膜中高导电性与高透过率之间的矛盾。H的掺杂可以显著降低ZnO基透明导电薄膜的电阻率,这是由于H一方面作为施主可以提供电子从而提高了自由载流子浓度;另一方面与ZnO晶界中的O-结合降低了晶界势垒,提高了载流子迁移率。利用H掺杂,可以在Al掺杂量降低10倍的情况下,仍然能获得低电阻率(6.3×10-4 Ω·cm)的透明导电薄膜,同时其近红外波段(1 200 nm)透光率从64%提高到90%。这种具有高导电性和高透光性的透明导电薄膜可以应用于各类薄膜太阳能电池中以提升器件效率。 相似文献
13.
基于低温重氧空位锐钛矿半导体的态密度计算,在同等条件下研究取不同大小模型的锐钛矿做适量浓度的氧空位存在,分别对进入导带的相对平均电子数和氧空位类杂质的散射迁移率进行计算,之后对电导率进行类比,发现锐钛矿半导体的导电性能对适量浓度低的氧空位有利可行得到了证明.同时,低温重氧空位的条件下,锐钛矿半导体的电导率不仅与氧空位浓度有关,而且和进入导带的平均电子数有关,和氧空位散射的电子迁移率有关的正确结论.
关键词:
锐钛矿半导体
氧空位浓度
电导率
第一性原理计算 相似文献
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K. Ramamoorthy M. Jayachandran K. Sankaranarayanan Pankaj Misra L. M. Kukreja C. Sanjeeviraja 《Current Applied Physics》2004,4(6):679-684
Intrinsic epitaxial zinc oxide (epi-ZnO) thin films were grown by laser-molecular beam epitaxy (L-MBE), i.e., pulsed laser deposition (PLD) technique using Johnson Matthey “specpure”-grade ZnO pellets. The effects of substrate temperatures on ZnO thin film growth, electrical conductivity (σ), mobility (μ) and carrier concentration (n) were studied. As well as the feasibility of developing high quality conducting oxide thin films was also studied simultaneously. The highest conductivity was found for optimized epi-ZnO thin films is σ=0.06×103 ohm−1 cm−1 (n-type) (which is almost at the edge of semiconductivity range), carrier density n=0.316×1019 cm−3 and mobility μ=98 cm2/V s. The electrical studies further confirmed the semiconductor characteristics of epi-n-ZnO thin films. The relationship between the optical and electrical properties were also graphically enumerated. The electrical parameter values for the films were calculated, graphically enumerated and tabulated. As a novelty point of view, we have concluded that without doping and annealing, we have obtained optimum electrical conductivity with high optical transparency (95%) for as deposited ZnO thin films using PLD. Also, this is the first time that we have applied PLD made ZnO thin films to iso-, hetero-semiconductor–insulator–semiconductor (SIS) type solar cells as transparent conducting oxide (TCO) window layer. We hope that surely these data be helpful either as a scientific or technical basis in the semiconductor processing. 相似文献
16.
ZnO nanoparticles codoped with Al and Li were chemically synthesized with a low temperature drying process. They are crystalline and can be made as small as 5 nm. Intense yellowish white photoluminescence was observed from smaller ZnO nanoparticles with a higher concentration of Al and Li. The photoluminescence peak consists of yellow and green emission bands. Both peak intensities increase with increasing the Al and Li concentrations and with decreasing the size of ZnO nanoparticles. The green and yellow emission bands were attributed to donor–acceptor-pair recombination involving Zn vacancies and lithium as the acceptor state, respectively, and the donor responsible for both emissions to oxygen vacancies. Both enhanced emissions by codoping may be explained by an increase in the number of electrons occupying the deep donor level on account of doping with Al. Although the yellowish white emission decays with time, passivation of the crystallite surface with poly(p-phenylene vinylene) suppresses the degradation. The observed high-intensity and stable yellowish white emission makes PPV-passivated ZnO nanoparticles, codoped with Al and Li, more attractive as a candidate for “white” phosphor. 相似文献