反应淀积氮化铝薄膜及其性质的研究

实验使用脉冲激光熔蚀金属铝靶,使溅射的物质粒子和真空室中的氮气反应以淀积氮化铝（ＡｌＮ）薄膜,淀积时引入氮气直流放电以促使Ａｌ和Ｎ发生完全反应制备高质量符合化学计量比的ＡｌＮ薄膜。讨论了脉冲能量密度、基底温度、气体放电对所沉积薄膜组织结构的影响。实验结果表明,当ＤＥ＝１．０Ｊ·ｃｍ－２,ＰＮ２＝１３．３３３ｋＰａ,Ｔｓｕｂ＝２００℃,Ｖ＝６５０Ｖ,ｆ＝５Ｈｚ,ｄＳ－Ｔ＝４ｃｍ时,高质量的ＡｌＮ薄膜被成功地沉积于Ｓｉ（１００）基片上。分析表明薄膜是具有高取向性的ＡｌＮ（１００）多晶膜,薄膜的能带间隙约为６．２ｅＶ,其电阻率和击穿电场分别为２×１０１３Ω·ｃｍ和３×１０６Ｖ·ｃｍ－１。     

用PECVD法在金属衬底上沉积氮化硅薄膜

采用等离子体增强化学气相沉积（ＰＥＣＶＤ）方法在４０Ｃｒ钢（含Ｃｒ０．８％～１．１％）或铜等金属基片上沉积氨化硅薄膜。沉积温度为２５０℃时，制备的薄膜厚度为０．２～０．４μｍ，电阻率为８×１０￣（１６）Ω·ｃｍ，介质击穿场强达到１×１０￣７Ｖ／ｃｍ。用ＸＰＳ谱研究了薄膜的结构和成分，并分析了沉积时不同的工艺参数对薄膜绝缘耐压性能的影响。     

BESOI薄膜的缺陷分析和应力研究

用机械减薄和氧化剥层法获得表层硅厚度约０．４μｍ的ＢＥＳＯＩ薄膜。对这种薄膜用Ｓｅｃｃｏ腐蚀液腐蚀并分析了缺陷种类，计量了缺陷密度。用波长为０．５１４５μｍ的激光Ｒａｍａｎ谱测量了ＢＥＳＯＩ薄膜和界面附近的应力密度。结果表明，该薄膜的主要缺陷为氧化层错，密度约１．８×１０３／ｃｍ２，总的缺陷密度为２．６×１０３／ｃｍ２，张应力密度δ≤５×１０３Ｎ／ｃｍ２。     

多元多色HgCdTe红外探测器

简要介绍利用不同波段的微型滤光片和不同响应波段的多元ＨｇＣｄＴｅ红外探测器,叙述了通过精密镶嵌技术组合而成的四波段２１５～２２５μｍ、８４～８９μｍ、１０３～１１３μｍ和１１５～１２５μｍ８８元多元多色探测器的设计原理和特性,以及多元多色探测器的组合工艺,并给出了各个通道的响应光谱特性和探测器的工作性能。研制成功的８８元多色红外探测器每个通道的平均探测率和响应率分别为：Ｄ２．１５～２．２５＝１．２×１０１２ｃｍＨｚ１／２／Ｗ和Ｒ２．１５～２．２５＝５．０×１０６Ｖ／Ｗ,Ｄ８．４～８．９＝７．０×１０１０ｃｍＨｚ１／２／Ｗ和Ｒ８．４～８．９＝１．６×１０４Ｖ／Ｗ,Ｄ１０．３～１１．３＝４．０×１０１０ｃｍＨｚ１／２／Ｗ和Ｒ１０．３～１１．３＝４．３×１０３Ｖ／Ｗ,Ｄ１１．５～１２．５＝３．０×１０１０ｃｍＨｚ１／２／Ｗ和Ｒ１１．５～１２．５＝３．３×１０３Ｖ／Ｗ,文中对这些结果进行了分析和讨论。     

0.15μm薄膜全耗尽MOS/SOI器件的设计和研制

利用自己开发的二维数值深亚微米ＳＯＩ器件模拟软件,较为详细地分析了沟道长度小于０．２μｍ的ＳＯＩ器件的阈值电压特性、穿通和击穿特性、亚阈值特性以及直流稳态特性等．通过这些模拟和分析计算,给出了沟道长度为０．１８、０．１５和０．１μｍ的薄膜全耗尽ＳＯＩ／ＭＯＳ器件的设计方案,并根据该设计方案成功地研制出了性能良好的沟道长度为０．１５μｍ的凹陷沟道ＳＯＩ器件．沟道长度为０．１５μｍ薄膜全耗尽凹陷沟道ＳＯＩ器件的亚阈值斜率为８７ｍＶ／ｄｅｃ,击穿电压为１．６Ｖ,阈值电压为０．４２Ｖ,电源电压为１．５Ｖ时的驱动电     

CdTe／ZnS复合钝化膜的界面电学特性研究

利用ＭＩＳ结构研究了长、中、短波碲镉汞材料，新型热蒸发ＣｄＴｅ／ＺｎＳ钝化膜界面电学特性及其与工艺条件的关系．结果表明，ＣｄＴｅ／ＺｎＳ双层膜界面电学参数依赖于界面预处理条件，在适当的工艺条件下，平带电压几乎为０，固定电荷密度为－４×１０１０ｃｍ－２，慢态密度为５．１×１０１０ｃｍ－２，界面态密度为２．７×１０－１１ｅＶ－１．ｃｍ－２．     

分子束外延HgCdTe／GaAs的生长和光伏探测器的研制

文中报导了用分子束外廷工艺在ＧａＡｓ（２１１）Ｂ衬底上生长了较高质量的中、长波ＨｇＣｄＴｅ薄膜材料。生长后的材料通过退火进行转型和调节电性参数。选择的组分分别为ｘ＝０．３３０和０．２２６的两种材料，７７Ｋ时载流子浓度和迁移率分别为ｐ＝６．７×１０１５ｃｍ－３、ｕｐ＝２６０ｃｍ２Ｖ－１ｓ－１和４．４５×１０１５ｃｍ－３、４１０ｃｍ２Ｖ－１ｓ－１。研制了平面型中、长波线列光伏探测器，其典型的探测器Ｄ分别为５．０×１０１０ｃｍＨｚ１／２Ｗ－１和２．６８×１０１０ｃｍＨｚ１／２Ｗ－１（１８０°视场下），其中６４元线列中波探测器与ＣＭＯＳ电路芯片在杜瓦瓶中耦含后读出并实现了红外成像演示。     

氮掺杂富勒烯薄膜电学性质的研究

在氮气气氛中用石墨电弧法合成了氮掺杂富勒烯．质谱、紫外、红外分析等手段证实了样品中含有Ｃ５９Ｎ、Ｃ５９Ｎ２、Ｃ５９Ｎ４、Ｃ５９Ｎ６以及Ｃ７０Ｎ２等分子团簇，对蒸发制备的薄膜进行３小时２００℃退火测得其室温电导率为１e－６（Ｓ／ｃｍ），激活能为０．６９ｅＶ（常温），０．５６ｅＶ（高温）．     

氢化非晶硅带隙态密度光诱导变化的研究

报导了与Ｓｔａｅｂｌｅｒ－Ｗｒｏｎｓｋｉ效应相关的氢化非晶硅（α－Ｓｉ：Ｈ）带隙态密度的光诱导变化，结果表明光照将使α－Ｓｉ：Ｈ带隙上半部分态密度的分布发生变化，采用ＡＭ１太阳光谱＊光照两小时使得导带迁移率边以下０．７ｅＶ处的带隙态密度从４×１０１６ｃｍ－３ｅＶ－１，增大到１×１０１７ｃｍ－３ｅＶ－１。     

高迁移率Si／Si_（0．7）Ge_（0．3）／Si调制掺杂异质结构的生长和输运性质

采用计算机控制的快速辐射加热、超低压ＣＶＤ（ＲＲＨ／ＶＬＰ－ＣＶＤ）方法生长了Ｓｉ／Ｓｉ０．７Ｇｅ０．３／Ｓｉｐ－型调制掺杂双异质结构．研究了该结构的输运性质，其空穴霍尔迁移率高达３００ｃｍ２／Ｖ·ｓ（３００Ｋ，薄层载流于浓度ｐｓ为２．６e１３ｃｍ－２）和８４００ｃｍ２／Ｖ·ｓ（７７Ｋ，ｐｓ为１．１e１３ｃｍ－２）．     

Theoretical investigation of the electronic structure,optical, elastic,hardness and thermodynamics properties of jadeite

A detailed theoretical study of the electronic structure, optical, elastic and thermodynamics properties of jadeite have been performed by means of the first principles based on the state-of-the-art of density functional theory within the generalized gradient approximation. The optimized lattice constants and the atomic positions are in good agreement with experimental data. The total density of states and partial density of states of jadeite have been discussed. The energy gap has been calculated along the Γ direction found to be 5.338 eV, which shows that jadeite has wide direct band gap. The optical properties, such as the dielectric function, refractive index, extinction coefficient, reflectivity coefficient, loss function and absorption coefficient for [100] and [001] directions have been described for the first time in the energy range 0–40 eV. The elastic constants, bulk modulus, Young׳s modulus, anisotropic factor and Poisson׳s ratio have been calculated. Furthermore, the Vickers hardness and Debye temperature of jadeite have been predicted. The calculated values of all above parameters are compared with the available experimental values.     

Theoretical investigation of mechanical,optoelectronic and thermoelectric properties of BiGaO3 and BiInO3 compounds

The cubic BiGaO₃ and BiInO₃ perovskite oxides have been investigated for their structural stability, mechanical and opto-electronic properties by employing the density functional theory. The exchange-correlation effects have been modeled with Perdew–Burke–Ernzerhof generalized gradient approximation, while the improved evaluation of electronic properties has been achieved by using the Tran–Blaha modified form of semi-local Becke–Johnson functional. Structural properties are calculated and the thermodynamics stability of BiGaO₃ and BiInO₃ in the cubic perovskite structure has been established in terms of enthalpies of formation. Furthermore, elastic coefficients such as C_ij, bulk modules B, anisotropy factor, shear modulus G, Young’s modulus Y, Poisson’s ratio ν, and B/G ratio are predicted. Band structure calculations reveal that investigated compounds have an indirect band gap between the occupied O 2p and unoccupied Bi 6p orbitals. The optical response of BiGaO₃ and BiInO₃ are also inspected by computing the complex dielectric function, refractive index, absorption coefficient, extinction coefficient, reflectivity and optical conductivity for radiation with energy up to 16 eV. The important thermoelectric properties of the compounds are described in terms of thermal conductivity, electrical conductivity, Seebeck coefficient and figure of merit.     

K+掺杂对SnO2-LiZnVO4系湿敏陶瓷性能的影响

为了提高 SnO_2-LiZnVO_4系湿敏材料的性能,采用共沉淀法制备出 SnO_2-K_2O-LiZnVO_4系纳米湿敏粉体。考察了液相掺杂 K+对材料湿敏性能、复阻抗特性和电容特性的影响。实验结果表明,采用共沉淀法制备纳米粉体并使K+液相掺杂量为 2.5%(摩尔分数),可使湿敏材料低湿电阻小、灵敏度适中,适当的 K+添加量可明显改善 SnO_2-LiZnVO_4系纳米材料的感湿特性。     

Effect of annealing temperature on structural,electrical and optical properties of spray pyrolytic nanocrystalline CdO thin films

Nanocrystalline CdO thin films were prepared onto a glass substrate at substrate temperature of 300 °C by a spray pyrolysis technique. Grown films were annealed at 250, 350, 450 and 550 °C for 2.5 h and studied by the X-ray diffraction, Hall voltage measurement, UV-spectroscopy, and scanning electron microscope. The X-ray diffraction study confirms the cubic structure of as-deposited and annealed films. The grain size increases whereas the dislocation density decreases with increasing annealing temperature. The Hall measurement confirms that CdO is an n-type semiconductor. The carrier density and mobility increase with increasing annealing temperature up to 450 °C. The temperature dependent dc resistivity of as-deposited film shows metallic behavior from room temperature to 370 K after which it is semiconducting in nature. The metallic behavior completely washed out by annealing the samples at different temperatures. Optical transmittance and band gap energy of the films are found to decrease with increasing annealing temperature and the highest transmittance is found in near infrared region. The refractive index and optical conductivity of the CdO thin films enhanced by annealing. Scanning electron microscopy confirms formation of nano-structured CdO thin films with clear grain boundary.     

Structural,elastic, electronic and thermodynamic properties of uranium filled skutterudites UFe4P12: First principle method

We present a theoretical study of structural, elastic, thermodynamic, and electronic properties of the uranium filled skutterudite UFe₄P₁₂. We use the full-potential linear muffin–tin orbital (FP-LMTO) method in which the local density approximation (LDA) is used for the exchange-correlation (XC) potential. The lattice parameter at equilibrium, the bulk modulus, its pressure derivative, the elastic constants and the band structure energy of the filled skutterudite UFe₄P₁₂ are calculated and systematically compared to available theoretical and experimental data. Herein, we use the total energy variation as function of strain technique to determine independent elastic constants and their pressure dependence. Furthermore, using quasi-harmonic Debye model with phonon effects, the effect of pressure P and temperature T on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature and the heat capacity of UFe₄P₁₂ are investigated for the first time. Band structure of UFe₄P₁₂ indicates a tendency of forming a pseudo-gap that appears above the Fermi level at Γ point. This is a unique characteristic of skutterudite, especially when a single phosphorous p-band crosses the Fermi level. The crossing band is, indeed, pushed down by the repulsion of U f-resonance states.     

Effect of substrate temperature on structural,morphological, optical and electrical properties of MnIn2S4 thin films prepared by nebulizer spray pyrolysis technique

Manganese indium sulphide (MnIn₂S₄) thin films were deposited using an aqueous solution of MnCl₂, InCl₃ and (NH₂)₂CS in the molar ratio 1:2:4 by simple chemical spray pyrolysis technique. The thin film substrates were annealed in the temperature range between 250 and 350 °C to study their various physical properties. The structural properties as studied by X-ray diffraction showed that MnIn₂S₄ thin films have cubic spinel structure. The formation of cube and needle shaped grains was clearly observed from FE-SEM analysis. The energy dispersive spectrum (EDS) predicts the presence of Mn, In and S in the synthesized thin film. From the optical studies, it is analyzed that the maximum absorption co-efficient is in the order between 10⁴ and 10⁵ cm⁻¹ and the maximum transmittance (75%) was noted in the visible and infrared regions. It is noted that, the band gap energy decreases (from 3.20 to 2.77 eV) with an increase of substrate temperature (from 250 to 350 °C). The observations from photoluminescence studies confirm the emission of blue, green, yellow and red bands which corresponds to the wavelength range 370–680 nm. Moreover, from the electrical studies, it is observed that, as the substrate temperature increases the conductivity also increases in the range 0.29–0.41×10⁻⁴ Ω⁻¹ m⁻¹. This confirms the highly semiconducting nature of the film. The thickness of the films was also measured and the values ranged between 537 nm (250 °C) to 483 nm (350 °C). This indicates that, as the substrate temperature increases, the thickness of the film decreases. From the present study, it is reported that the MnIn₂S₄ thin films are polycrystalline in nature and can be used as a suitable ternary semiconductor material for photovoltaic applications.     

Optical,morphological and electrical studies of Zn:PbS thin films

Structural, electrical, and optical properties of undoped and Zn doped lead sulfide (PbS) thin films are benign reported in this paper. The subjected films were grown on glass substrates at 25 °C by a chemical bath deposition (CBD) method. The concentration of Zn in the deposition bath represented by the ratio [Zn²⁺]/[Pb²⁺] was varied from 0% to 5%. It was found that the film׳s grains decreased in size with increasing Zn content in the film. XRD data showed the polycrystalline nature of the film its crystal orientation peak intensities decreased with higher doping concentration of Zn. Atomic force microscopy (AFM) measurements revealed that the surface roughness of the films decreased due to zinc doping as well. However, with increasing of the dopant concentration from 0% to 5%, the average transmittance of the films varied over the range of 35–75%. The estimated optical band (E_g) gaps of undoped and Zn doped PbS thin films were in the range of 0.72–1.46 eV. Hall Effect measurements electrical resistivity, carrier concentration and Hall mobility have been determined for the titled film as functions on the Zn content within the film׳s textures. The overall result of this work suggested that the Zn:PbS film is a good candidate as an absorber layer in the modern solar cell devices.     

Effect of rhenium doping on various physical properties of single crystals of MoSe2

Effect of rhenium doping is examined in single crystals of MoSe₂ viz. MoRe_0.005Se_1.995, MoRe_0.001Se_1.999 and Mo_0.995Re_0.005Se₂, which is grown by using the direct vapor transport (DVT) technique. The grown crystals are structurally characterized by X-ray diffraction, by determining their lattice parameters a and c, and X-ray density. Also, the Hall effect and thermoelectric power (TEP) measurements show that the single crystals exhibit a p-type semiconducting nature. The direct and indirect band gap measurements are also undertaken on these semiconducting materials.     

Effect of rhenium doping on various physical properties of single crystals of MoSe2

正Effect of rhenium doping is examined in single crystals of MoSe_2 viz.MoRe_(0.005)Se_(1.995), MoRe_(0.001)Se_(1.999) and Mo_(0.995)Re_(0.005)Se_2,which is grown by using the direct vapor transport(DVT) technique. The grown crystals are structurally characterized by X-ray diffraction,by determining their lattice parameters a and c,and X-ray density.Also,the Hall effect and thermoelectric power(TEP) measurements show that the single crystals exhibit a p-type semiconducting nature.The direct and indirect band gap measurements are also undertaken on these semiconducting materials.     

Effect of Co doping on structural, optical, electrical and thermal properties of nanostructured ZnO thin films

Nanocrystalline Zn1-x CoxO(where x varies from 0 to 0.04 in steps of 0.01) thin films were deposited onto glass substrate by the spray pyrolysis technique at a substrate temperature of 350 ℃. The X-ray diffraction patterns confirm the formation of hexagonal wurtzite structure. The crystal grain size of these films was found to be in the range of 11–36 nm. The scanning electron micrographs show a highly crystalline nanostructure with different morphologies including rope-like morphology for undoped ZnO and nanowalls and semispherical morphology for Co-doped Zn O. The transmittance increases with increasing Co doping. The optical absorption edge is observed in the transmittance spectra from 530 to 692 nm, which is due to the Co2C absorption bands corresponding to intraionic d–d shifts. The direct and indirect optical band gap energies decrease from 3.05 to 2.75 eV and 3.18 to 3.00 eV, respectively for 4 mol% Co doping. The electrical conductivity increases with increasing both the Co doping and temperature, indicating the semiconducting nature of these films. The temperature dependence thermal electromotive force measurement indicates that both undoped and Co-doped ZnO thin films show p-type semiconducting behavior near room temperature. This behavior dies out beyond 313 K and they become n-type semiconductors.