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CdZnTe晶体通常利用其(333)晶面的X射线衍射摇摆曲线来检测(111)晶面的结晶质量.本文根据CdZnTe晶体(333)面摇摆曲线实验结果,首次提出了CdZnTe晶体摇摆曲线的不唯一现象.摇摆曲线的这种不唯一现象是样品绕(111)面法线方向旋转360.过程中,晶体的(333)面和(333)面在同一衍射几何中都发生了布拉格衍射,优化扫描后得出两个摇摆曲线.分析了CdZnTe晶体(333)面和(-333)面对X射线散射能力,得出CdZnTe晶体(333)面的衍射强度小于(-333)面的衍射强度,所以在同等实验条件下,对同一CdZnTe晶片(333)面的摇摆曲线的强度比(333)面摇摆曲线的强度低. 相似文献
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CdZnTe晶体通常利用其(333)晶面的X射线衍射摇摆曲线来检测(111)晶面的结晶质量.本文根据CdZnTe晶体(333)面摇摆曲线实验结果,首次提出了CdZnTe晶体摇摆曲线的不唯一现象.摇摆曲线的这种不唯一现象是样品绕(111)面法线方向旋转360.过程中,晶体的(333)面和(333)面在同一衍射几何中都发生了布拉格衍射,优化扫描后得出两个摇摆曲线.分析了CdZnTe晶体(333)面和(-333)面对X射线散射能力,得出CdZnTe晶体(333)面的衍射强度小于(-333)面的衍射强度,所以在同等实验条件下,对同一CdZnTe晶片(333)面的摇摆曲线的强度比(333)面摇摆曲线的强度低. 相似文献
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描述了一种汽相生长n~+-n-n~+多层外延InP的简便方法及其生长程序.用本方法生长的具有特殊掺杂分布的n~+-n-n~+外延InP,制得了高效率InP耿氏二极管.在49.2 GHz下,连续波输出功率为232mW效率高达7.52%. 相似文献
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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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获得高电阻率的、完整性好的CdZnTe晶体是研制高性能的CdZnTe γ射线探测器的关键.运用热力学关系估算了Cd1-xZnx熔体平衡分压,尝试以Cd1-xZnx合金源替代Cd源进行Cd0.8Zn0.2Te晶片的热处理,研究了退火对Cd0.8Zn0.2Te晶片质量的影响.结果表明:在1069K下用Cd0.8Zn0.2合金源(PZn=0.122×105Pa和PCd=1.20×105Pa)对Cd0.8Zn0.2Te晶片退火5天以上,可提高晶体电阻率一个数量级和晶体红外透过率10%以上,并可消除或减小晶片中的Te沉淀,同时避免了Zn的损失,改善Zn的径向分布.可见,采用Cd1-xZnx合金源代替Cd源控制进行CZT退火处理优于仅采用Cd源控制的退火处理. 相似文献
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用不加籽晶的垂直汽相生长法生长了CdTe单晶。具有小平面的高质量晶体示出了比~6N源材料高的纯度。已发现生长率与生长装料中的过量Te有很大关系。在制备装料时观察到过量Te为0.001~0.2mol%的情况下最大生长率为2g/日左右。晶体和机械-化学抛光片的x射线分析和金相研究说明单晶结晶质量是高的。晶体具有高电阻率(≥10~8Ωcm)并具有核辐射探测特性。 相似文献
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CdZnTe晶片中的Zn组分的研究 总被引:2,自引:0,他引:2
用X 射线双晶衍射、光致发光谱和红外透射光谱研究了CdZnTe 晶体中的Zn 的组分.研究表明透射光谱的Syllaios经验公式结果与X 射线双晶衍射和光致发光谱精确测量结果对比,偏差小于4% .透射光谱可以做为测量Zn 组分的常规方法 相似文献
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Recent progress in CdZnTe crystals 总被引:3,自引:0,他引:3
CdZnTe crystals were grown by vertical gradient freezing (VGF) method with a Cd reservoir for controlling the Cd pressure
under conditions such that the crystals are in equilibrium with a Cd vapor corresponding to the minimum deviation from stoichiometry.
The precipitate size became smaller by a post growth annealing method in the VGF furnace after the crystal growth without
using wafer annealing. The size became less than 2 μm. Precipitate-free crystals were also grown by controlling the cooling
method. In addition, the carrier concentration of p-type CdZnTe crystals was reduced using polycrystals grown in pBN boats.
We have found that the carrier concentration of p-type ingots is dependent on Na and Li impurity concentrations. 相似文献
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碲锌镉晶体中存在着各种典型晶体缺陷,其缺陷研究一直倍受关注,X射线衍射形貌术是一种非破坏性地研究晶体材料结构完整性、均匀性的有效方法.采用反射式X射线衍射形貌术对碲锌镉衬底的质量进行了研究,并将衬底的X射线衍射形貌与Everson腐蚀形貌进行了对比分析,碲锌镉衬底的X射线衍射形貌主要有六种特征类型,分别对应不同的晶体结构或缺陷,包括均匀结构、镶嵌结构、孪晶、小角晶界、夹杂、表面划伤,对上述特征类型进行了详细的分析.目前,衬底的X射线衍射形貌主要以均匀结构类型为主,划伤和镶嵌结构缺陷基本已消除,存在的晶体缺陷主要以小角晶界为主.通过对比分析碲锌镉衬底和液相外延碲镉汞薄膜的X射线衍射形貌,发现小角晶界等晶体结构缺陷会延伸到外延层上,碲锌镉衬底质量会直接影响碲镉汞外延层的质量,晶体结构完整的衬底是制备高质量碲镉汞外延材料的基础. 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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Study of contacts to CdZnTe radiation detectors 总被引:1,自引:0,他引:1
This study characterizes, for the first time, contacts to CdZnTe radiation detectors by measuring the dark noise spectra as
a function of the applied bias. The noise currents are correlated with the dc dark current-voltage characteristics of CdZnTe
x-ray and gamma-ray detectors. In order to identify and separate the role of the contacts in the overall performance, the
measured noise phenomena is correlated with detector configuration and contact design as well as the growth method of the
CdZnTe crystals, contact technology, and passivation. Several contact technologies (electroless gold, and a number of evaporated
metallic contacts including gold, indium, zinc, titanium, aluminum, and platinum contacts) are compared. Contacts to CdZnTe
crystals grown by high pressure Bridgman are compared with contacts to CdZnTe crystals grown by modified Bridgman. Contacts
of resistive detectors as well as of Schottky detectors are reported. Large area symmetric contacts are compared with small
area pixelized contacts. The role of the metallization used for contacts, the role of surface effects and passivation, and
the role of contact design are discussed. 相似文献
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A. Hossain A.E. Bolotnikov G.S. Camarda R. Gul K.H. Kim K. Kisslinger G. Yang L.H. Zhang R.B. James 《Journal of Electronic Materials》2012,41(10):2908-2911
We investigated structural defects in CdZnTe detector-grade crystals grown under different conditions. Here, we report our findings from high-resolution electron microscopy [transmission electron microscopy (TEM) and scanning TEM (STEM)] and scanning electron microscopy integrated with energy-dispersive x-ray spectroscopy to characterize the material’s structural and chemical composition. Combining these techniques gave us important information about the defects, their concentration, and the elemental composition of the CdZnTe crystals. Our experimental observations demonstrated some distinct nanostructural defects in the crystals that may play a major role in device performance. 相似文献
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Csaba Szeles Scott E. Cameron Stephen A. Soldner Jean-Olivier Ndap Michael D. Reed 《Journal of Electronic Materials》2004,33(6):742-751
The high-pressure electro-dynamic gradient (HP-EDG) crystal-growth technology has been recently developed and introduced at
eV PRODUCTS to grow large-volume, semi-insulating (SI) CdZnTe single crystals for room-temperature x-ray and gamma-ray detector
applications. The new HP growth technology significantly improves the downstream CdZnTe device-fabrication yield compared
to earlier versions of the HP crystal-growth technology because of the improved structural and charge-transport properties
of the CdZnTe ingots. The new state-of-the-art, HP-EDG crystal-growth systems offer exceptional flexibility and thermal and
mechanical stability and allow the growth of high-purity CdZnTe ingots. The flexibility of the multi-zone heater system allows
the dynamic control of heat flow to optimize the growth-interface shape during crystallization. This flexibility combined
with an advanced control system, improved system diagnostics, and realistic heat-transport modeling provides an excellent
platform for continuing process development. Initial results on large-diameter (140 mm), SI Cd1−xZnxTe (x=0.1) ingots grown in low temperature gradients with the HP-EDG technique show reduced defect density and complete elimination
of ingot cracking. The increased single-crystal yield combined with the improved charge transport allows the fabrication of
large-volume, high-sensitivity, high energy-resolution detector devices at increased yield. The CdZnTe ingots grown to date
produced large-volume crystals (≥1cm3) with electron mobility-lifetime product (μτe) in the (3–7) × 10−3 cm2/V range. The lower-than-desired charge-transport uniformity of the HP-EDG CdZnTe ingots is associated with the high density
of Te inclusions formed in the ingots during crystallization. The latest process-development efforts show a reduction in the
Te-inclusion density, an increase of the charge-transport uniformity, and improved energy resolution of the large-volume detectors
fabricated from these crystals. 相似文献
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The depth of the damaged layer forming on the surface of the CdZnTe crystals during standard mechanical treatment of them
is determined by the microhardness measurement and chemical selective etching. The rates of chemical etching of the surface
of the CdZnTe crystals in the solutions of bromine in methanol with various bromine concentrations are determined. 相似文献
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S. Terterian M. Chu D. Ting L. C. Wu C. C. Wang M. Szawlowski G. Vissor P. N. Luke 《Journal of Electronic Materials》2003,32(7):796-802
A large number of room-temperature detectors have been produced from CdZnTe crystals grown with 10% Zn and 1.5% excess tellurium
by the low-pressure, vertical-Bridgman technique. Radiation spectra obtained by these crystals using a 241Am source reveal the characteristic 59.5-keV line as well as the six low-energy peaks, which include the Cd and Te escape
peaks. Similarly, 57Co spectra obtained also show a very well-defined 122-keV peak with a 3:1 peak-to-valley ratio. Seven CdZnTe crystals have
been grown for reproducibility studies. Four of these crystals have resistivities over 1E9 Ω-cm. Considering that the indiumdoping
level is on the order of 2E15 cm−3, the reproducibility is excellent. The theoretical basis of the high-resistivity phenomenon in CdZnTe is discussed in reference
to a previous paper. The uniformity of these 6-in.-long CdZnTe crystals is studied, and various measurements are carried out,
both laterally and vertically, along the boule. It is determined that, in general, roughly a 3.5-in. section near the middle
of the 6-in. boule has sufficient resistivity for producing radiation detectors. This nonuniformity along the vertical direction
is caused mostly by the composition change of Cd, Zn, Te, and In-doping level in the growth melt caused by differences in
the segregation coefficients of these elements. Although, variations in resistivity are seen across some of the wafer slices,
most show very good uniformity with high breakdown voltage. Some of the variations are attributed to the different grains
within the boule. Similar results are seen in the measured radiation spectra obtain on 4 mm × 4 mm × 2 mm samples from different
locations across the wafer, where some samples show well-resolved secondary peaks, while others display only the primary spectral
lines. 相似文献
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研究了HgCdTe液相外延薄膜表面两类宏观缺陷的形成原因.研究表明,大部分表面凹陷点(void)缺陷的形成是由衬底的蜡沾污所引入的,而表面凸起点(hill-like)是由衬底边缘脱落的CdZnTe微颗粒造成的,通过控制外延生长前的衬底处理过程,可以抑制这两类缺陷,从而生长出零(宏观)缺陷密度的优质HgCdTe外延薄膜. 相似文献