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分析了利用垂直布里奇曼法生长碲锌镉晶体的工艺条件,如坩埚的材质和形状、炉体温场、固液界面形状、生长速率以及采用籽晶等生长条件对晶体单晶率和质量的影响,并提出了优化垂直布里奇曼法生长CdZnTe晶体的条件。 相似文献
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碲锌镉(CZT,CdZnTe)晶片是生长红外焦平面列阵所用碲镉汞(HgCdTe)薄膜的衬底材料.为了满足碲镉汞液相外延的性能要求,采用化学机械抛光可获得平面度高、粗糙度低、无损伤层的碲锌镉晶片表面。通过对抛光结构的机械运动分析,建立了抛光过程中各参数对工艺指标的影响,通过实验优化工艺参数获得高质量的抛光效果。 相似文献
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研究了碲锌镉衬底(111)晶面的不同极性对水平推舟液相外延生长碲镉汞薄膜的影响。实验结果显示,(111)A面碲锌镉衬底水平液相外延生长碲镉汞薄膜材料组分和厚度均与常规(111)B面碲锌镉衬底碲镉汞薄膜材料相当;碲镉汞母液在采用(111)A面、(111)B面衬底进行液相外延生长的碲镉汞薄膜上接触角分别为(50±2)°和(30±2)°,结合微观模型分析确认碲镉汞母液在碲镉汞薄膜(111)A面存在更大的表面张力;观察并讨论了(111)A面碲镉汞与(111)B面碲镉汞薄膜材料表面微观形貌的差别;实验获得的(111)A面碲镉汞薄膜XRD半峰宽为33.1arcsec。首次报道了(111)晶面选择对母液残留的影响,研究结果表明,采用(111)A面碲锌镉衬底进行碲镉汞水平推舟液相外延生长,能够在不降低晶体质量的情况下,大幅减小薄膜表面母液残留。 相似文献
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Jonathan S. Wright Aaron L. Washington II Martine C. Duff Arnold Burger Michael Groza Liviu Matei Vladimir Buliga 《Journal of Electronic Materials》2013,42(11):3119-3124
The variation in bulk resistivity during infrared (IR) illumination above 950 nm of state-of-the-art CdZnTe (CZT) crystals grown using the traveling heating method or the modified Bridgman method is documented. The change in steady-state current with and without illumination is also evaluated. The influence of secondary phases (SP) on current–voltage (I–V) characteristics is discussed using IR transmission microscopy to determine the defect concentration within the crystal bulk. SP present within the CZT are connected to the existence of deep, IR-excitable traps within the bandgap. 相似文献
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Samantha A. Hawkins Eliel Villa-Aleman Martine C. Duff Doug B. Hunter Arnold Burger Michael Groza Vladimir Buliga David R. Black 《Journal of Electronic Materials》2008,37(9):1438-1443
CdZnTe (CZT) crystals can be grown under controlled conditions to produce high-quality crystals to be used as room-temperature
radiation detectors. Even the best crystal growth methods result in defects, such as tellurium secondary phases, that affect
the crystal’s performance. In this study, CZT crystals were analyzed by micro-Raman spectroscopy. The growth of Te rich areas
on the surface was induced by low-power lasers. The growth was observed versus time with low-power Raman scattering and was
observed immediately under higher-power conditions. The detector response was also measured after induced Te enrichment. 相似文献
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红外光热吸收效应作为一种无损伤非接触的检测技术,已经被广泛用于硅等半导体材料中的微缺陷表征分析.采用光热吸收技术对碲锌镉晶体中的缺陷进行扫描成像分析时发现了一种连续性的光貌相条纹,并对这些条纹的形成机理进行了研究.研究表明碲锌镉晶体中的这种连续性条纹源自于光热测试系统中入射光的干涉,这种干涉和入射光参数、测试样品的厚度、禁带宽度以及热导率等材料特性密切相关.最后,实验通过优化红外光热吸收测量系统获得了碲锌镉材料中的微缺陷结构及其在样品深度方向的三维分布图像. 相似文献
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G. A. Carini G. S. Camarda Z. Zhong D. P. Siddons A. E. Bolotnikov G. W. Wright B. Barber C. Arnone R. B. James 《Journal of Electronic Materials》2005,34(6):804-810
High-energy transmission x-ray diffraction techniques have been applied to investigate the crystal quality of CdZnTe (CZT).
CdZnTe has shown excellent performance in hard x-ray and gamma detection; unfortunately, bulk nonuniformities still limit
spectroscopic properties of CZT detectors. Collimated high-energy x-rays, produced by a superconducting wiggler at the National
Synchrotron Light Source’s X17B1 beamline, allow for a nondestructive characterization of thick CZT samples (2–3 mm). In order
to have complete information about the defect distribution and strains in the crystals, two series of experiments have been
performed. First, a monochromatic 67 keV x-ray beam with the size of 300×300 μm2 was used to measure the rocking curves of CZT crystals supplied by different material growers. A raster scan of a few square
centimeter area allowed us to measure the full-width at half-maximum (FWHM) and shift in the peak position across the crystal.
The rocking curve peak position and its FWHM can be correlated with local stoichiometry variations and other local defects.
Typically, the FWHM values ranging from 8.3 arcsec to 14.7 arcsec were measured with the best crystal used in these measurements.
Second, transmission white beam x-ray topography (WBXT) was performed by using a 22 mm×200 μm beam in the energy range of 50 keV to 200 keV. These types of measurements allowed for large area, high-resolution (50 μm) scans of the samples. Usually, this technique is used to visualize growth and process-induced defects, such as dislocations,
twins, domains, inclusions, etc. the difference in contrast shows different parts of the crystal that could not be shown otherwise.
In topography, good contrast is indicative of a high quality of the sample, while blurred gray shows the presence of defects.
Correlation with other techniques (e.g., infrared (IR) mapping and gamma mapping) was also attempted. Our characterization
techniques, which use highly penetrating x-rays, are valid for in-situ measurements, even after electrical contacts have been
formed on the crystal in a working device. Thus, these studies may lead to understanding the effects of the defects on the
device performance and ultimately to improving the quality of CZT material required for device fabrication. It is important
to study crystals from different ingot positions (bottom, center, and top); consequently, more systematic studies involving
scans from center to border are planned. 相似文献
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利用气相外延技术在CdZnTe衬底上生长Hg1-xCdxTe薄膜材料,通过在不同晶向、不同极性、不同晶向偏离角度CdZnTe衬底上的外延结果发现,CdZnTe衬底对外延形貌的影响非常大。(111)面衬底上外延形貌明显优于(211)面衬底的外延形貌。对于同是<111>CdZnTe晶向的衬底,(111)Cd面CdZnTe衬底上的外延形貌明显优于(111)Te面。对于(111)Cd面CdZnTe衬底,当晶向偏离角度不同时,其外延形貌也有差异,晶向偏离角越小表面形貌越好。 相似文献
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S. N. Agbo S. Dobrovolskiy G. Wegh R. A. C. M. M. van Swaaij F. D. Tichelaar P. Sutta M. Zeman 《Progress in Photovoltaics: Research and Applications》2014,22(3):346-355
This contribution investigates the effect of seeding the growth of thin film microcrystalline silicon (µc‐Si : H) deposited by radio frequency plasma‐enhanced chemical vapor deposition on the material properties of µc‐Si : H film and the device performance of p‐i‐n and n‐i‐p µc‐Si : H solar cells. By means of Raman measurement, x‐ray diffraction (XRD) and transmission electron microscopy (TEM), we investigate the structure of seeded µc‐Si : H. In particular, the effect of seed layers on the crystallinity development is investigated. Measurements of the depth profile of the crystalline mass fraction using Raman spectroscopy show that seed layers lead to a more rapid and uniform crystallinity development in growth direction. The amorphous incubation layer is suppressed and crystallization begins directly from onset of film growth without evolving through the intermediate growth phases. From TEM analyses, we observe that crystal sizes are not affected by seed layers. Horizontal cracks are however observed to dominate the early growth of µc‐Si : H in p‐i‐n solar cell and this is reduced upon seeding. For the n‐i‐p cells, these cracks are not affected by seeding. XRD results also indicate that the use of seed layers does not affect the crystal sizes but affects the direction of preferential orientation. Solar cell external parameters show that seeding of p‐i‐n solar cells leads mainly to increase in short‐circuit current density, Jsc with a slight drop in open‐circuit voltage, Voc. For the n‐i‐p cells, a reverse effect is observed. In this case, the Voc increases and the Jsc decreases. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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K. Yasuda K. Mori Y. Kubota K. Kojima F. Inukai Y. Asai T. Nimura 《Journal of Electronic Materials》1998,27(8):948-953
Growth characteristics of (100)-oriented CdZnTe layers grown by atmospheric-pressure metalorganic vapor phase epitaxy have
been studied using dimethylzinc (DMZn), dimethylcadmium (DMCd), diethyltelluride (DETe), and dimethyltelluride (DMTe) as precursors.
Variations of Zn composition and layer growth rate were examined by changing the DMZn supply ratio, defined as DMZn/(DMCd+DMZn),
where the precursors are expressed in appropriate units of flow rate, from 0 (no DMZn) to 1.0 (no DMCd), while keeping the
total group II supply rate constant. The growth rate of CdZnTe layers was found to decrease monotonically with increase of
the DMZn supply ratio. On the other hand, the Zn composition x of grown layers increased gradually up to x=0.04 with increase
of the DMZn supply ratio from 0 to 0.8, beyond which the Zn composition increased abruptly to ZnTe. The abrupt transition
of Zn composition was suppressed by increasing the VI/II ratio. The growth mechanism of CdZnTe layers was studied based on
the observed growth characteristics of CdTe and ZnTe. A higher desorption rate from the growth surface for Zn species than
for Cd species, and a higher rate of CdTe formation than ZnTe formation are believed to cause the observed growth characteristics.
CdZnTe layers with high crystal quality were grown in a wide range of Zn compositions. The full-width at half-maximum values
for x-ray double-crystal rocking-curve measurements were lower than 320 arc-sec for x<0.3 and x>0.75. 相似文献