CIGS薄膜(InGa)2Se3-富Cu-富In(Ga)的演变

采用三步共蒸发工艺顺序沉积铜铟镓硒(CuInGaSe2,CIGS)薄膜.薄膜的厚度、组份、晶相结构分别由台阶仪、X射线荧光光谱仪(XRF)和X射线衍射仪(XRD)来表征.在(In,Ga)2Se3预制层-富Cu相的演变过程中,依次发生以下相变:Cu(In,Ga)5Se8、Cu(In,Ga)3Se5、Cu2(In,Ga)4Se7(或Cu(In,Ga)2Se3.5)、Cu(In,Ga)Se2(液相CuxSe).在富Cu相-富In(Ga)相的演变过程中,依次发生以下相变:Cu(In,Ga)Se2(液相CuxSe)、Cu2(In,Ga)4Se7(或Cu(In,Ga)2Se3.5)、Cu(In,Ga)3Se5、Cu(In,Ga)5Se8.对这两个演变过程中薄膜的生长机理和结构特性进行了讨论.     

CdO对In2O3电导和气敏性能的影响

为探索新型CdO-In2O3材料的气敏性能,用化学共沉淀法制备了CdO掺杂的In2O3微粉,研究了CdO掺杂对In2O3电导和气敏效应的影响。结果表明CdO和In2O3间能形成有限固溶体In2-CdxO3(0≤x≤0.02);In1.98Cd0.02O3x的电导比纯In2O3小得多;900℃下热处理4h所得的x(CdO)为2%的In2O3传感器在183℃工作温度下,对45μmol·L–1C2H5OH的灵敏度达276、响应–恢复时间只有3s和180s。有望开发为一类新型酒敏材料。     

Boron retarded diffusion in the presence of indium or germanium

Experimental results of germanium (Ge) and indium (In) preamorphization by ion-implantation show that the diffusion of boron (B) is retarded by the presence of Ge or In and that this retardation is more important than the preamorphization (dechanneling) effect. Result shows that In retards B diffusion more than Ge and the retardation effect due to In becomes greater with increasing retained dose of In. Larger In doses cause larger strain, which results in more B being tied up in immobile clusters near the surface. In order to achieve adequate retained dose of In, the implanted dose of In must be increased to 5/spl times/10/sup 15/ cm/sup -2/. After anneal, the junction depth (at 10/sup 18/ cm/sup -3/) is reduced from 628 /spl Aring/ in the control wafer (no In co-implant) to 480 /spl Aring/.     

二氧化钌水洗工艺的改进

常用二氧化钌水洗钠离子工艺, 用容器沉淀二氧化钌, 抽取上部溶液, 加水洗。用这种方法, 二氧化钌产品收率低, 约７５％ 。用玻沙漏斗抽滤, 加入热去离子水洗方法, 二氧化钌产品收率高, 约９９％ , 制备出的二氧化钌质量符合要求, 降低了生产成本。     

Structural and electrical properties of co-evaporated In, Ga-rich CIGS thin films

The CIGS thin films are prepared by co-evaporation of elemental In, Ga and Se on the substrates of Mo-coated glasses at400℃ followed by co-evaporation of elemental Cu and Se at 550℃. We study the structural and electrical properties usingXRD, XRF and Hall effect measurements. In general, Cu(In,Cra)5Se8 phase exists when Cu/(In Ga) ratio is from 0.17 to0.27, Cu(In,Ga)3Se5 phase exists for Cu/(In Ga) ratio between 0.27 and 0.41, Cu2(In,Ga)4Se7 and Cu(In,Ga)2Se3.5 phasesexist for Cu/(In Ga) ratio between 0.41 and 0.61, and OVC(or ODC) and CuIn0.7Ga0.3 Se2 phases exist when Cu/(In Ga)ratio is from 0.61 to 0.88. With the increase of Cu/(In Ga) ratio, the carrier concentrations of the films gradually increase,but the electrical resistivity gradually decreases.     

Role of contacts in characterization of deep traps in semi-insulating GaAs by thermally stimulated current spectroscopy

The role of contacts in characterization of traps in semi-insulating (SI) GaAs by thermally stimulated current (TSC) methods has been demonstrated by comparing alloyed In and soldered In contacts. Alloyed In contacts, which have an ohmic characteristic, assure high sensitivities in both TSC and temperature dependent photocurrent (PC), and both are important for determining the trap concentrations in SI GaAs. On the other hand, soldered In contacts, which act like Schottky barriers, cause a significant reduction of both PC and TSC, particularly at low temperatures, and can lead to a misinterpretation of TSC results.     

从PZT体系看无铅压电陶瓷的可能应用

总结了主要以(Bi0.5Na0.5)TiO3和NaNbO3为基的无铅压电陶瓷的性能，以Pb(Ti，Zr)TiO3基二元系、三元系压电陶瓷的性能与应用为参考，分析了无铅压电陶瓷可能的器件应用。此外，还对拓宽无铅压电陶瓷应用需要改进的性能提出了建议。     

新型负阻HBT构成的非稳多谐振荡器研究

报道了由超薄基区负阻异质结双极晶体管(UTBNDRHBT)构成的非稳多谐振荡器,具有高速、可调控等优点。对其电压控制脉冲频率调制效应进行了实验研究,观察到了仅由基极电压(V_(BE))即可控制脉冲间距和脉冲宽度;对实验现象给出了相应分析,并指出了此电路的应用前景。     

Preparation of defined structures on very thin foils for characterization of AFM probes

In atomic force microscopy (AFM), knowledge of the probe (tip) geometry is a critical factor for obtaining reproducible images. This is particularly important for measurements in the contact mode, in which a certain amount of wear of the probe always occurs affecting the image quality of small, flat and/or larger surface structures. In addition to probe geometry, the slope of the probe with respect to the sample is of importance. In this work, probe geometry is determined by the use of structured foils obtained using focused ion beam (FIB). In this manner, we demonstrate the possibility of determining the AFM probe geometry and the slope on the basis of differently-sized structures. An established algorithm was implemented for the reconstruction of the probes. The shape of FIB structured foils was determined separately by scanning electron microscopy (SEM).     

面向对注氢硅片中微结构的影响

把不同面向的注氢硅片制成横截面样品,在高分辨率透射电子显微镜下进行观察,发现衬底面向对其中的微结构有明显的影响.首先表现为衬底中主要出现平行于正表面的氢致片状缺陷,即(10 0 )衬底中,主要出现平行于正表面的{ 10 0 }片状缺陷,而(111)衬底中出现的主要是平行于正表面的{ 111}片状缺陷.其原因是注入引起垂直正表面的张应变.另外,面向的影响还表现为,(10 0 )衬底中出现的{ 113}缺陷在(111)衬底中不出现.在(111)衬底中出现的晶格紊乱团和空洞在(10 0 )衬底中不出现.从而推测,{ 111}片状缺陷的形成不发射自间隙原子,而(10 0 )片状缺陷的形成将发射自     

Thermoelectric Properties of Two-Phase PbTe with Indium Inclusions

The thermoelectric figure of merit (zT) can be increased by introduction of additional interfaces in the bulk to reduce the thermal conductivity. In this work, PbTe with a dispersed indium (In) phase was synthesized by a matrix encapsulation technique for different In concentrations. x-Ray diffraction analysis showed single-phase PbTe with In secondary phase. Rietveld analysis did not show In substitution at either the Pb or Te site, and this was further confirmed by room-temperature Raman data. Low-magnification (~1500×) scanning electron microscopy images showed micrometer-sized In dispersed throughout the PbTe matrix, while at high magnification (150,000×) an agglomeration of PbTe particles in the hot-pressed samples could be seen. The electrical resistivity (ρ) and Seebeck coefficient (S) were measured from 300 K to 723 K. Negative Seebeck values showed all the samples to be n-type. A systematic increase in resistivity and higher Seebeck coefficient values with increasing In content indicated the role of PbTe-In interfaces in the scattering of electrons. This was further confirmed by the thermal conductivity (κ), measured from 423 K to 723 K, where a greater reduction in the electronic as compared with the lattice contribution was found for In-added samples. It was found that, despite the high lattice mismatch at the PbTe-In interface, phonons were not scattered as effectively as electrons. The highest zT obtained was 0.78 at 723 K for the sample with the lowest In content.     

锌掺杂量对In_2O_3电导和气敏性能的影响

用化学共沉淀和热处理法于pH11.5～12.5时,用(NH4)2CO3作沉淀剂,制备了Zn2+掺杂的In2O3微粉。研究了Zn2+掺杂量对In2O3气敏元件电导和气敏性能的影响。结果发现,ZnO与In2O3可形成有限固溶体In2-xZnxO3(0≤x≤0.10);In1.95Zn0.05O3气敏元件在223℃工作温度下,对浓度为4.5×10–7mol/L的C2H5OH的灵敏度高达174.4,且选择性也好。     

Influence of Mn incorporation on MBE growth of (In,Mn)N

(In,Mn)N has been grown onc-plane sapphire substrates by plasma-assisted molecular beam epitaxy. The dependence of Mn incorporation on the growth conditions was studied in situ by reflection high-energy electron diffraction and ex situ by high-resolution x-ray diffraction and secondary-ion mass spectroscopy. It was found that the growth temperature significantly affected the Mn replacement in In sites. The optimized growth temperature was about 280°C. Mn incorporation was also affected by the (In+Mn)/N ratio and the Mn/(In+Mn) flux ratio. N-rich growth conditions were found to be favored for Mn incorporation and replacement in the In sites.     

Numerical optimization of large-scale fiber-optic splitting tree uniformity

In order to split the optical power of a signal into many fibered outputs, large-scale optical splitting trees (splitters) are used. In most applications, the optical power should remain constant from output to output. Large-scale splitting trees (typically 1 : 32 or 1 : 128) may be composed of a single-stage or of cascaded small splitters (typically 1 : 2). In the former case, power uniformity is determined by the design and manufacturing tolerances. In the latter case, considered here, uniformity may be optimized by a proper choice of the positions of the small splitters in the tree. Simulations show that less than 1-dB uniformity may be reached.     

Inversion of conductivity type in ZnSe single crystals obtained by the method of free growth

ZnSe:In and (ZnSe:In):Zn single crystals obtained by the method of free growth were studied. Inversion of the conductivity type was attained by annealing crystals in an atmosphere of saturated selenium vapors. Hole conductivity was attained for the first time in (ZnSe:In):Zn crystals with an initially high electron conductivity (3–5 Ω^?1 cm^?1). The origin of donor and acceptor centers responsible for the conductivity of crystals was ascertained.     

The impact of timing errors on the performance of linear DS-CDMAreceivers

In this paper, an asynchronous direct-sequence code-division multiple-access (DS-CDMA) communication system operating over an additive white Gaussian noise (AWGN) channel is considered. In many applications, the near-far problem can be the limiting factor for the capacity of a DS-CDMA system. Several near-far resistant receivers have, therefore, been proposed (e.g., the decorrelating receiver). These receivers assume perfect knowledge of the propagation delay from all users to the receiver. In practice, the delays are estimated and therefore subject to errors. The performance degradation these errors impose on linear detectors, especially the decorrelating detector, is the topic of this paper     

Study of the electroluminescent properties of crystalline silicon wafers in devices based on junctions of indium-doped zinc oxide and porous silicon

In this study we obtained electroluminescent devices (ELD) based on junctions of indium doped zinc oxide (ZnO:In) and porous silicon layers (PSL). The PSL were obtained by electrochemical etching with different types and resistivities of silicon wafers. In the visible part of the electromagnetic spectrum, the porous silicon (PS) exhibits photoluminescence (PL) that is centered around 680 nm. Once the devices were obtained, they were optically and electrically characterized. The PSL were coated with ZnO:In film, which was gotten by the ultrasonic spray pyrolysis technique (USP). When the devices were electrically polarized they showed optical response in the regions corresponding to the visible and infrared band of the electromagnetic spectrum. The observed electroluminescence (EL) in the visible region goes from 400 to 750 nm and the corresponding emission of the infrared part is around 750–1150 nm. The devices presented luminescent spots on the surface which were visible to the naked eye. The analysis of the results shows that the emission source in the visible part is attributed to the filaments present in the PS, and also to the ZnO:In films and the emission in the infrared part is associated to the silicon substrate. The electrical characterization was carried out by current–voltage curves (I–V) that show in the devices a rectifying behavior.     

Maximizing Burst Erasure-Correction Capability of MDS Codes

In general, an (n,k) maximum distance separable (MDS) code over GF(p^m) can not correct all burst erasures of length (n-k)m over GF(p). In this letter, we constructively show that such a linear MDS code over GF(p^m) can be modified to correct all burst erasures of length up to (n-k)m over GF(p), while maintaining its MDS property over GF(p^m)     

五结太阳能电池设计与模拟

设计了与太阳光谱更匹配的五结太阳能电池(Al)GaInP/AlGa(In)As/(In)GaAs/GaInAsN/Ge,并首次应用APSYS软件对其电特性进行了模拟。与四结太阳能电池和传统的InGaP/GaAs/Ge结构进行对比,结果表明该结构各结电流更加匹配,获得了较高的转换效率。     

Effect of keyholes on the symbol error rate of space-time block codes

In multiple-input multiple-output (MIMO) fading environments, degenerate channel phenomena, so-called keyholes or pinholes, may exist under realistic assumptions where a MIMO channel has uncorrelated spatial fading between antenna arrays but a rank-deficient transfer matrix. In this letter, we analyze the average symbol error rate (SER) of orthogonal space-time block codes (STBCs) with M-PSK and M-QAM constellations over keyhole channels.