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1.
Au掺杂是改善光伏型HgCdTe红外探测器性能的一种技术途径,通过Au掺杂来取代HgCdTe材料中的本征的Hg空位,可以提高材料的少子寿命和少子扩散长度。采用液相外延技术生长了Au掺杂的HgCdTe外延材料,Au的掺杂浓度为~8×1015/cm3,通过富Hg退火技术来抑制材料中的Hg空位,Hg空位的浓度控制在1~2×1015/cm3。变温霍尔测试表明,退火材料中的受主杂质能级为8~12 meV,并且与退火条件相关。采用Au掺杂材料和离子注入成结工艺制备了截止波长为14 μm的甚长波红外焦平面器件,测试结果显示,用Au掺杂取代Hg空位掺杂,可以显著提高红外探测器的光响应率,探测器的内量子效率可以达到95%以上。 相似文献
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钱定榕 《红外与毫米波学报》1991,10(2):156-160
研究已表明掺杂HgCdTe中不存在对于自由载流子等离子体振荡的朗道阻尼,本文进一步研究了HgCdTe掺杂及随之产生的简并对自由载流子能量色散关系的影响,并将这种影响计入自由载流子的介电函数后,从理论上证明了掺杂窄禁带半导体中不存在朗道阻尼的现象是由于自由载流子能量色散关系变化引起其运动行为变化所致。 相似文献
4.
退火温度对ZnO掺杂ITO薄膜性能的影响 总被引:2,自引:2,他引:0
利用电子束蒸镀方法,在K8玻璃衬底上沉积ZnO掺杂ITO(ZnO-ITO)与ITO薄膜。研究不同退火温度对ZnO-ITO薄膜的微观结构的影响;对比分析了在不同退火温度条件下,ZnO-ITO和无掺杂ITO薄膜的光电性能。结果发现,ZnO-ITO薄膜具有较大的晶粒尺寸,随着退火温度的上升,晶体结构得到改善,表面粗糙度减小,薄膜的光电性能显著提高。ZnO-ITO薄膜经过500℃退火后得到最佳的综合性能,其表面均方根粗糙度(RMS)为32.52nm,电阻率为1.43×10-4Ω.cm;对442nm波长的光,透射率可达98.37%;与ITO薄膜相比,ZnO-ITO薄膜具有显著的抗PEDOT:PSS溶液腐蚀的能力。 相似文献
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通过介质膜ZnS、CdTe薄膜材料的Ar+束溅射沉积研究,结合HgCdTe器件工艺,成功制备了以ZnS、CdTe双层介质膜为绝缘层的HgCdTeMIS器件;通过对器件的C-V特性实验分析,获得了CdTe/HgCdTe界面电学特性参数.实验表明溅射沉积介质膜CdTe+ZnS对HgCdTe的表面钝化已经可以满足HgCdTe红外焦平面器件表面钝化的各项要求. 相似文献
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MBE生长HgCdTe材料的As掺杂退火的研究 总被引:3,自引:0,他引:3
1 引言 近年来,随着碲镉汞(HgCdTe或MCT)红外焦平面(IRFPA)技术的快速发展,器件对材料的电学性质、面积和均匀性等参数的要求迅速提高。要实现载流子在较大范围内的浓度控制以 相似文献
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通过改进推舟液相外延技术,成功地在(211)晶向Si/CdTe复合衬底上进行了HgCdTe液相外延生长,获得了表面光亮的HgCdTe外延薄膜.测试结果表明,(211)Si/CdTe复合衬底液相外延HgCdTe材料组分及厚度的均匀性与常规(111)CdZnTe衬底HgCdTe外延材料相当;位错腐蚀坑平均密度为(5~8)×105 cm-2,比相同衬底上分子束外延材料的平均位错密度要低一个数量级;晶体的双晶半峰宽达到70″左右.研究结果表明,在发展需要低位错密度的大面积长波HgCdTe外延材料制备技术方面,Si/CdTe复合衬底HgCdTe液相外延技术可发挥重要的作用. 相似文献
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通过改进推舟液相外延技术,成功地在(211)晶向Si/CdTe复合衬底上进行了HgCdTe液相外延生长,获得了表面光亮的HgCdTe外延薄膜.测试结果表明,(211)Si/CdTe复合衬底液相外延HgCdTe材料组分及厚度的均匀性与常规(111)CdZnTe衬底HgCdTe外延材料相当;位错腐蚀坑平均密度为(5~8)×105 cm-2,比相同衬底上分子束外延材料的平均位错密度要低一个数量级;晶体的双晶半峰宽达到70″左右.研究结果表明,在发展需要低位错密度的大面积长波HgCdTe外延材料制备技术方面,Si/CdTe复合衬底HgCdTe液相外延技术可发挥重要的作用. 相似文献
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复合衬底CdTe/ZnTe/Si的晶体质量是导致随后外延的HgCdTe外延膜高位错密度的主要原因之一,因此如何提高复合衬底CdTe/Si晶体质量是确保硅基碲镉汞走上工程化的关键所在。降低复合衬底CdTe/Si位错密度方法一般有:生长超晶格缓冲层、衬底偏向、In-situ退火和Ex-situ退火等,本文主要研究Ex-situ退火对复合衬底CdTe/Si晶体质量的影响。研究表明复合衬底经过Ex-situ退火后位错密度最好值达4.2×105cm-2,双晶半峰宽最好值达60arcsec。 相似文献
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A. Parikh S.D. Pearson B.K. Wagner C.J. Summers 《Journal of Electronic Materials》1997,26(9):1065-1069
A study is reported of the dynamics of dopant incorporation in iodine doped CdTe. Using a mathematical formulation, the iodine
doping profiles in CdTe and HgCdTe have been fitted to experiment to obtain material parameters such as the bulk and surface
diffusion and the segregation energy. Dopant profile fitting showed that iodine diffusion was insignificant and gave an iodine
segregation energy of 0.6 eV and a surface diffusivity enhancement factor of 300 at a growth temperature of 230°C. The model
was used to determine the effect of the growth rate and temperature for particular growth conditions. 相似文献
12.
Dual-band infrared detectors made on high-quality HgCdTe epilayers grown by molecular beam epitaxy on CdZnTe or CdTe/Ge substrates 总被引:2,自引:0,他引:2
P. Ballet F. Noël F. Pottier S. Plissard J. P. Zanatta J. Baylet O. Gravrand E. De Borniol S. Martin P. Castelein J. P. Chamonal A. Million G. Destefanis 《Journal of Electronic Materials》2004,33(6):667-672
In this paper, we present all the successive steps for realizing dual-band infrared detectors operating in the mid-wavelength
infrared (MWIR) band. High crystalline quality HgCdTe multilayer stacks have been grown by molecular beam epitaxy (MBE) on
CdZnTe and CdTe/Ge substrates. Material characterization in the light of high-resolution x-ray diffraction (HRXRD) results
and dislocation density measurements are exposed in detail. These characterizations show some striking differences between
structures grown on the two kinds of substrates. Device processing and readout circuit for 128×128 focal-plane array (FPA)
fabrication are described. The electro-optical characteristics of the devices show that devices grown on Ge match those grown
on CdZnTe substrates in terms of responsivity, noise measurements, and operability. 相似文献
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M. Tanaka K. Ozaki H. Nishino H. Ebe Y. Miyamoto 《Journal of Electronic Materials》1998,27(6):579-582
We employed AgNO3 solutions for doping Ag in liquid phase epitaxy (LPE) grown Hg0.78Cd0.22Te epilayers and found that the minority carrier lifetimes became longer so that the diode properties improved. After annealing
LPE grown Hg(1-x)Cd(x)Te layers (x=0.22) in Hg atmosphere, the epilayers were immersed in an AgNO3 solution at room temperature. The typical carrier concentrations of holes was 3 × 1016 cm−3 at 77K. These values were almost the same as for the nondoped wafers. Also, its acceptor level was 3 to 4 meV. This shows
that the Ag was activated. The doped crystals have lifetimes several times longer than those of the nondoped crystals. Numerical
fitting showed the lifetime was limited mostly by the Auger 7 process. The Shockley-Read-Hall recombination process was not
effective. To examine the Ag-doped wafer, we fabricated photodiodes using standard planar technology. The diodes have an average
zero-bias resistance of several MΩ and a shunt resistance of about 1 GΩ for a 10 μm cutoff wavelength at 78K. These values
are about four times higher than those of nondoped diodes. The photo current is also two times higher at the same pixel size.
This shows that the quantum efficiency is increased. The extension of the lifetime contributes to the high resistance and
the high quantum efficiency of the photodiode. 相似文献
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基于GaAs/Si材料中位错的运动反应理论,修正获得CdTe/Si和HgCdTe/Si外延材料中的位错运动反应模型.采用快速退火方法对Si基HgCdTe外延材料进行位错抑制实验研究,实验结果与理论曲线基本吻合,从理论角度解释了不同高温热处理条件对材料体内位错的抑制作用.对于厚度为4~10μnn的CdTe/Si进行500... 相似文献
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L. A. Almeida Y. P. Chen J. P. Faurie S. Sivananthan David J. Smith S. -C. Y. Tsen 《Journal of Electronic Materials》1996,25(8):1402-1405
We have systematically studied the growth of CdTe (lll)B on Si(001)with different atomic step structures, defined uniquely
by miscut tilt angle and direction. X-ray double crystal rocking curve (DCRC) analysis has been used to evaluate the crystalline
quality and twin content of the films. High-resolution electron microscopy has been used to examine the CdTe(lll)B/Si(001)
interface and to follow the microstructural evolution as a function of distance from the interface. Our results show that
the formation of double domains and twins is very sensitive to the tilt parameters. When growth conditions are optimized,
twins are not observed at distances greater than about 2.5 microns from the substrate surface. The best quality films exhibit
a DCRC FWHM of 60 arc sec, for a film thickness of 17 μm, the lowest value ever reported for heteroepitaxial growth of CdTe
on Si or GaAs. In efforts to improve the nucleation process, precursors such as Te and As have been used, and we have shown
that they improve the stability of the heterointerface. 相似文献
16.
Characterization of CdTe for HgCdTe surface passivation 总被引:2,自引:0,他引:2
L. O. Bubulac W. E. Tennant J. Bajaj J. Sheng R. Brigham A. H. B. Vanderwyck M. Zandian W. V. Mc Levige 《Journal of Electronic Materials》1995,24(9):1175-1182
The objectives of this work are to study the physical and chemical structure of CdTe films using secondary ion mass spectrometry
(SIMS) and atomic force miroscopy (AFM) and to demonstrate the usefulness of these analytical techniques in determining the
characteristics of CdTe-passivation films deposited by different techniques on HgCdTe material. Three key aspects of CdTe
passivation of HgCdTe are addressed by different analytical tools: a) morphological microstructure of CdTe films examined
by atomic force microscopy; b) compositional profile across the interface determined by Matrix (Te)—SIMS technique; c) concentration
of various impurities across the CdTe/HgCdTe structure profiled by secondary ion-mass spectrometry. 相似文献
17.
Lijie Zhao J. S. Speck R. Rajavel J. Jensen D. Leonard T. Strand W. Hamilton 《Journal of Electronic Materials》2000,29(6):732-735
Transmission electron microscopy (TEM) was used to evaluate the microstructure of molecular beam epitaxy (MBE) grown (211)B
oriented HgCdTe films. TEM analysis of in-situ doped p-on-n and n-p-n device structures will be presented. Under fully optimized
growth conditions the substrate-epilayer interface is free of threading dislocations and twins, and a high degree of structural
integrity is retained throughout the entire device structure. However, under non-optimal growth conditions that employ high
Hg/Te flux ratios, twins can be generated in the p-type layer of p-on-n device structure, resulting in roughness and facetting
of the film surface. We propose a mechanism for twin formation that is associated with surface facetting. TEM evaluation of
voids, threading dislocations and Te-precipitates in HgCdTe films are also discussed. 相似文献
18.
P. S. Wijewarnasuriya M. D. Lange S. Sivananthan J. P. Faurie 《Journal of Electronic Materials》1995,24(5):545-549
We have studied the minority-carrier lifetime on intentionally indium-doped (211)B molecular beam epitaxially grown Hg1-xCdxTe epilayers down to 80K with x ≈ 23.0% ± 2.0%. Measured lifetimes were explained by an Auger-limited band-to-band recombination
process in this material even in the extrinsic temperature region. Layers show excellent electron mobilities as high as ≈2
x 105 cm2v-1s-1 at low temperatures. When the layers are compensated with Hg vacancies, results show that the Schockley-Read recombination
process becomes important in addition to the band-to-band processes. From the values of τn0 and τp0 of one sample, the obtained defect level is acceptor-like and is somewhat related to the Hg vacancies. 相似文献
19.
Polycrystalline Cadmium Telluride (CdTe) thin films were prepared on glass substrates by thermal evaporation at the chamber ambient temperature and then annealed for an hour in vacuum ~1×10−5 mbar at 400 °C. These annealed thin films were doped with copper (Cu) via ion exchange by immersing these films in Cu (NO3)2 solution (1 g/1000 ml) for 20 min. Further these films were again annealed at different temperatures for better diffusion of dopant species. The physical properties of an as doped sample and samples annealed at different temperatures after doping were determined by using energy dispersive x-ray analysis (EDX), x-ray diffraction (XRD), Raman spectroscopy, transmission spectra analysis, photoconductivity response and hot probe for conductivity type. The optical band gap of these thermally evaporated Cu doped CdTe thin films was determined from the transmission spectra and was found to be in the range 1.42–1.75 eV. The direct energy band gap was found annealing temperatures dependent. The absorption coefficient was >104 cm−1 for incident photons having energy greater than the band gap energy. Optical density was observed also dependent on postdoping annealing temperature. All samples were found having p-type conductivity. These films are strong potential candidates for photovoltaic applications like solar cells. 相似文献
20.
Robert Furstenberg Michael R. Papantonakis C.A. Kendziora 《Journal of Electronic Materials》2009,38(8):1533-1538
We report an infrared photo-thermal excitation imaging and spectroscopy study of CdTe and CdZnTe substrates as well as HgCdTe/CdZnTe
and HgCdTe/Si epilayers. The applicability, advantages, and limitations of the technique as a tool for both ex situ and in situ monitoring of bandgap, thickness, and growth temperature are discussed. We show that photo-thermal imaging allows for direct
visual imaging of the bandgap region of CdTe and CdZnTe substrates. We also show that photo-thermal spectroscopy can provide
epilayer thickness information independent of the dielectric function. The method is orthogonal to existing optical characterization
techniques and could be combined with them for improved accuracy. 相似文献