高温超导红外探测器的研制

用在两种衬底(SrTiO_3和LaAlO_3)上生长的YBa_2Cu_3O_(7-x)。薄膜制成高灵敏的热敏型高温超导红外探测器。经500K标准黑体的测量,在10Hz调制频率时,以SrTiO_3为衬底的器件,D~*(500,10,1)达8.2×10~8cm·Hz~(1/2)/W,NEP(500,10,1)达1.6×10~(10)W/Hz~(1/2);以LaAlO_3为衬底的器件,NEP(500,10,1)达10~(-11)W/Hz~(1/2)。还测量并分析了D~*和NEP随频率的变化和噪声频谱。     

两种新型红外探测器

华北光电技术研究所近期研制成下述两种红外探测器: 1.碲锡铅异质结红外探测器 这是以碲锡铅晶体作衬底、用液相“异质结”外延技术制成的红外探测器。响应波长为8～12μm,适于室温目标的探测、成象。可应用于红外前视、医用热成象、遥感、跟踪、污染监控等方面。该器件的探测率D一般大于1×10~(10)cm·Hz 1/2/W,最高的D≥4～5×10~(10)cm·Hz 1/2/W;峰值波长λ_p≥10μm。经     

高温超导红外探测器的研制

采用高温超导薄膜YBaCuO和GdBaCuO研制超导红外探测器。将超导膜通过光刻湿法腐蚀成形后,用剥离技术制备金电极并合金化,热压焊接4根引线,超导芯片安装在抽空窗口为KRS-5的红外探测器杜瓦瓶中。77K超导红外探测器的测试性能为:NEP_(min)=1.6×1~(-9)W/Hz~(1/2),D_(bbmax)~*=4.15×10~7cmHz~(1/2)/W,R_(max)(500K)=136V/W,τ_(min)=8.8ms,λ_p=13.6μm。对超导器件的稳定性考察得出:微桥寿命最短,长桥次之,蛇形较长。一支蛇形器件经过数十次的冷热循环和电测试,寿命已超过5个月。     

"风云二号"卫星用水汽/热红外双波段探测器

报导了我国第一颗静止气象卫星"风云二号"卫星多通道扫描辐射计中使用的水汽/热红外双波段6.3～7.6μm、10.5～12.5μm四元碲镉汞红外探测器性能.探测器工作温度T=100K时,热红外波段探测率D*(10.5～12.5)为3.4×1010cmHz1/2/W,波段响应率R(10.5～12.5)为3.0×104(V/W);水汽波段探测率D*(6.3～7.6)为1.1×1011cmHz1/2/W,波段响应率R(6.3～7.6)为6.1×104(V/W).探测器经过环境应力筛选,密封筛选,电应力筛选,抗太阳辐照试验,电子、质子辐照试验以及高真空、低温工作寿命试验,获得了探测器可靠性寿命数据,器件失效率小于7.5×10-6/h.     

双色红外探测器研究

为适应遥感、遥测及精确制导技术的发展,我们已研制出一定性能的CdS/HgCdTe(0.3～0.5μm/3～5μm)、Si/InSb(0.3～1.05μm/3～5μm)、Si/HgCdTe(0.3～1.05μm/3～5μm)、HgCdTe/LiTaO_3(3～5μm/8～14μm)、HgCdTe/HgCdTe(3～5μm/8～14μm)等多种双色红外探测器。其中HgCdTe/HgCdTe(3～5μm/8～14μm)光导双色探测器的峰值探测率D~*(5.1,980,1)=2.1×10~(10)cmHz~(1/2)/W,D~*(9.8,980,1)=8.1×10~9cmHz~(1/2)/W, 峰值响应率R(5.1,980,1)=1.3×10~4V/W,R(9.8,980,1)=373V/W。文中介绍了双色探测器的设计、结构、制备及器件的性能水平。     

长波双色Al_xGa_(1-x)As/GaAs量子阱红外探测器的研制

介绍了长波双色AlxGa1-xAs/GaAs多量子阱红外探测器单元的设计、制作和测试。器件光敏面面积为300μm×300μm,光吸收峰值波长分别为10.8、11.6μm;采用垂直入射光耦合的工作模式,65K温度2V偏压下,两个多量子阱区的暗电流分别为4.23×10-6、4.19×10-6A;黑体探测率分别为1.5×109、6.7×109cm.Hz1/2/W;响应率分别为0.063、0.282A/W。GaAs基量子阱红外探测器(QWIP)材料生长和加工工艺成熟、大面积均匀性好、成本低、不同波段之间的光学串音小,使得AlGaAs/GaAsQWIP在制作多色大面阵方面具有明显的优势。     

热释电探测器

一、引言热释电探测器是70年代中取得重要进展的一种新型器件。目前最好的单元探测器探测率D(500,10,1)已达到5×10~9cm·Hz~(1/2)/W。我国从1970年开始研究这种探测器,其单元探测器性能已达到国际先进水平。但在热释电多元列阵及热释电/CCD混成探测器领域差距还很大。     

256×1甚长波量子阱红外焦平面研究

GaAs/AlGaAs量子阱红外探测器由于其所依据的GaAs基材料较为成熟的材料生长和器件制备工艺,使其特别适合于高均匀性、大面积红外焦平面的应用。报道了甚长波256×1元GaAs/AlGaAs多量子阱红外焦平面器件的研制成果, 探测器的峰值波长为15 μm,响应带宽大于1.5 μm。在40 K工作温度下,器件的平均黑体响应率Rp=3.96×106 V/W, 平均黑体探测率为D*=1.37×109 cm·Hz1/2/W, 不均匀性为11.3%, 并应用研制的器件获得了物体的热像图。     

具有宽带响应的GaAs／AlGaAs多量子阱红外探测器

报道具有宽带响应的130元线列GaAs/AlGaAs多量子阱红外探测器的研究进展.通过表面光栅耦合,采用垂直入射的工作模式,在T=80K时测得器件探测率的光谱响应曲线的半峰宽为4.3μm.在λ_p=9.5μm时的峰值探测率为4.89×10~9cmHz~(1/2)/W,电压响应率为2.89×10~4V/W.     

背照式InGaN紫外探测器的制备与数值模拟

研究了背照式InGaN p-i-n结构的紫外探测器的制备与数值模拟.通过低压金属有机化学气相沉积(MOCVD)方法生长p-GaN/i-InGaN/n-GaN外延片,采用标准的Ⅲ-Ⅴ族器件制备工艺,成功制备出p-i-n结构的InGaN紫外探测器.探测器台面半径为30 μm,在-5V偏压下暗电流为-6.47×10 1 2 A,对应的电流密度为2.29×10-7 A/cm2.该探测器响应波段为360～380 nm,在371 nm处达到峰值响应率为0.21 A/W,对应的外量子效率为70％,内量子效率为78.4％.零偏压下,优值因子R0A=5.66×107 Ω·cm2,对应的探测率D* =2.34×1013 cm·Hz1/2·W-1.同时,利用Silvaco TCAD软件进行数值模拟,响应率曲线仿真值与实验值拟合较好.     

Co3O4/Fe2O3异质结复合材料的制备及其紫外光光电探测性能

分别采用旋涂法和水热法在FTO衬底上制备Co₃O₄种子层和Co₃O₄薄膜,再在Co₃O₄薄膜上水热生长Fe₂O₃纳米棒,获得了高质量的Co₃O₄/Fe₂O₃异质结复合材料。通过改变Fe₂O₃前驱体溶液浓度来改变异质结复合材料中Fe₂O₃组分的含量。结果表明,Fe₂O₃纳米棒覆盖在呈网状结构的Co₃O₄薄膜上,随着Fe₂O₃前驱体溶液浓度即Fe₂O₃组分含量的增加,Co₃O₄/Fe₂O₃异质结复合材料对紫外光的响应逐渐增强,当Fe₂O₃前驱体溶液浓度为0.015mol/L时,异质结复合材料有着很好的光电稳定性,并表现出较高的响应率(12.5mA/W)和探测率(4.4×10¹⁰Jones)。     

In气氛退火对Cd0.9Zn0.1Te材料电阻率的影响研究

在不同温度条件下对Cd0.9Zn0.1Te晶片进行In气氛退火热处理,显著提高了Cd0.9Zn0.1Te材料的电阻率。通过实验测量和理论建模计算,得到了1 073、1 023和973K条件下In原子在Cd0.9Zn0.1Te晶片中的扩散系数分别为4.25×10-9 cm2·s-1、9.02×10-10 cm2·s-1和2.17×10-10 cm2·s-1,并且拟合出了1 073~973K范围内扩散系数和温度之间的函数关系表达式D(T)=2.15×exp(-1.9/k0T)及频率因子D0等数据。最后,对实验结果进行了简要的对比和分析解释。     

Molecular beam epitaxy of CdTe and Hg1-xCdxTe ON GaAs (100)

Using the molecular beam epitaxial (MBE) technique, CdTe and Hg_1-xCd_xTe have been grown on Cr-doped GaAs (100) sub-strates. A single effusion cell charged with polycrystal-line CdTe is used for the growth of CdTe films. The CdTe films grown at 200 °C with a growth rate of ~ 2 μm/hr show both streaked and “Kikuchi” patterns, indicating single crystalline CdTe films are smoothly grown on the GaAs sub-strates. A sharp emission peak is observed at near band-edge (7865 Å, 1.577 eV) in the photoluminescence spectrum at 77 K. For the growth of Hg_1-xCd_xTe films, separate sources of HgTe, Cd and Te are used. Hg_0.6Cd_0.4Te films are grown at 50 °C with a growth rate of 1.7 μm/hr. The surfaces are mirror-smooth and the interfaces between the films and the substrates are very flat and smooth. As-grown Hg_0.6Cd_0.4Te films are p-type and converted into n-type by annealing in Hg pressure. Carrier concentration and Hall mobility of an annealed Hg_0.6Cd_0.4Te film are 1 × 10¹⁷ cm^?3 and 1000 cm²/V-sec at 77 K, respectively.     

Enhanced superconductivity in Nd1+xBa2-xCu3O7+δby low oxygen partial pressure annealing

Previous work has shown that unlike YBa₂ Cu₃ O_7-δ (Y123), the Nd-Ba-Cu-O system exhibits a solid solution Nd_1+xBa_2-x Cu₃O_7+δ (Nd123ss) for 0.04≤ × ≤0.6.^1–3) An earlier paper showed that although the superconducting properties decrease nonlinearly for increasing x, T_c can be varied by increasing the annealing temperature without changing the low temperature oxygen soak.² The changes in microstructure and T_c with increasing x are analogous with Y123 with increasing δ except that the total hole concentration remained constant. T_c was modeled in terms of oxygen disorder resulting from Nd³⁺ atoms on the Ba sites relocating chain oxygens to anti-chain sites. The variability in T_c as a function of x and processing conditions can be explained by the number of fourfold coordinated coppers on the chain sites. In this paper, the model has been further substantiated by processing in 1% O₂. The annealing in a reduced oxygen partial pressure followed by a 450°C oxygen soak resulted in a marked increase in T_c compared to the 100% PO₂ anneal. The low PO₂ anneal favors pairing of Nd³⁺ substituting for Ba²⁺ to conserve oxygen ions, resulting in fewer disrupted fourfold-coordinated coppers thus increasing charge transfer from the planes to the chains.     

LaNiO3 and Cu3Ge contacts to YBa2Cu3O7-x films

Metallization of high-T_c superconductors using low resistivity metal oxides and Cu-Ge alloys has been investigated on high quality pulsed laser deposited epitaxial YBa₂Cu₃O_7-x (YBCO) films. Epitaxial LaNiO₃ (LNO) thin films have been grown on YBCO films at 700°C using pulsed laser deposition. The specific resistivity of LNO was measured to be 50 μΩ-cm at 300K which decreases to 19 μΩ-cm at 100K indicating good metallicity of the LNO films. The contact resistance of LNO-YBCO thin film interface was found to be reasonably low (of the order of 10^-4Ω-cm² at 77K) which suggests that the interface formed between the two films is quite clean and LNO can emerge as a promising metal electrode-material to YBCO films. A preliminary investigation related to the compatibility of Cu₃Ge alloy as a contact metallization material to YBCO films is discussed. The usage of other oxide based low resistivity materials such as SrRuO₃ (SRO) and SrVO₃ (SVO) for metallization of high-T_c YBCO superconductor films is also discussed.     

Memory Effect of Metal-Insulator-Silicon Capacitor with HfO<Subscript>2</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Multilayer and Hafnium Nitride Gate

Metal-insulator-silicon capacitors have been fabricated using novel insulators of SiO₂/HfO₂-Al₂O₃-HfO₂ (HAH)/Al₂O₃ and metallic HfN gate, exhibiting a program-erasable characteristic. The memory capacitor presents a large memory window of 2.4 V under +12 V program/–14 V erase for 10 ms, no erase saturation, and sufficient electron- and hole-trapping efficiencies such as an electron density of ∼7 × 10¹² cm^–2 under 13 V program for 0.5 ms and a hole density of ∼4 × 10¹² cm^–2 under –12 V erase for 0.5 ms. The observed properties are attributed to the introduction of high permittivity atomic-layer-deposited HAH/Al₂O₃ as well as high work function HfN gate. The related mechanism is addressed accordingly.     

用溶胶-凝胶法制备的Cu2Bi2Cr2O8薄膜 及其光学和铁磁性能研究

以硝酸铜Cu(NO₃)₂·3H₂O、硝酸铬Cr(NO₃)₃·9H₂O、硝酸铋Bi(NO₃)₃·3H₂O和乙二醇为原料,利用溶胶-凝胶工艺在石英衬底上制备了纳米Cu₂Bi₂Cr₂O₈薄膜。通过X射线衍射(X-Ray Diffraction, XRD)和拉曼测试对样品进行了表征。结果表明,Cu₂Bi₂Cr₂O₈薄膜具有良好的光学特性,其禁带宽度为1.49 eV;在磁性测试方面,Cu₂Bi₂Cr₂O₈薄膜呈现出了良好的铁磁性。     

Influence of the metal electrode on the characteristics of thermal Ta2O5 capacitors

The effect of various electrodes (Al, W, TiN) deposited by evaporation (Al) and sputtering (W, TiN) on the electrical characteristics of thermal thin film (15-35 nm) Ta₂O₅ capacitors has been investigated. The absolute level of leakage currents, breakdown fields, mechanism of conductivity, dielectric constant values are discussed in the terms of possible reactions between Ta₂O₅ and electrode material as well as electrode deposition process-induced defects acting as electrically active centers. The dielectric constant values are in the range 12-26 in dependence on both Ta₂O₅ thickness and gate material. The results show that during deposition of TiN and Al a reaction that worsens the properties of Ta₂O₅ occurs while there is not an indication for detectable reduction of Ta₂O₅ when top electrode is W, and the leakage current is 5-7 orders of magnitude lower as compared to Al and TiN-electroded capacitors. The high level of leakage current for TiN and Al gate capacitors are related to the radiation defects generated in Ta₂O₅ during sputtering of TiN, and damaged interface at the electrode due to a reaction between Al and Ta₂O₅, respectively. It is demonstrated that the quality of the top electrode affects the electrical characteristics of the capacitors and the sputtered W is found to be the best. The sputtered W gate provides Ta₂O₅ capacitors with a good quality: the current density <7 × 10⁻¹⁰ A/cm² at 1 V (0.7 MV/cm, 15 nm thick Ta₂O₅). W deposition is not accompanied by an introduction of a detectable damage leading to a change of the properties of the initial as-grown Ta₂O₅ as in the case of TiN electrode. Damage introduced during TiN sputtering is responsible for current deterioration (high leakage current) and poor breakdown characteristics. It is concluded that the sputtered W top electrode is a good candidate as a top electrode of storage capacitors in dynamic random access memories giving a stable contact with Ta₂O₅, but sputtering technique is less suitable (favorable) for deposition of TiN as a metal electrode due to the introduction of radiation defects causing both deterioration of leakage current and poor breakdown characteristics.     

具有低电压、低“迟滞效应”的C60薄膜晶体管

以C60为激活层,同时以聚合物/高K氧化物双绝缘层结构研制了N型有机场效应晶体管。结果表明,采用这种双层结构的绝缘层能够很好的将Ta2O5和PMMA的优点结合在一起,即既利用了Ta2O5的高介电常数又利用了PMMA与半导体层良好的界面接触特性。与采用单一Ta2O5或这PMMA绝缘层的器件相比,这种具有双层结构的器件性能大幅提升。最终研制了能够在10V低电压下正常工作的C60晶体管,其场效应迁移率、阈值电压和开关电流比分别为0.26 cm2/Vs, 3.2V和8.31×104。同时,利用修饰绝缘层PMMA的疏水性大大降低了这种具有双层结构的N型有机晶体管的“迟滞效应”,从而让器件工作时有较好的稳定性。     

Plasma anodization of evaporated Al-InP systems

Aluminium oxide-InP structures were fabricated by plasma anodization of evaporated Al-InP systems with intention of fabricating InP MISFETS. It was found that the resistivity and break-down strength of the A1₂O₃ film were influenced by the selection of the end point of the anodization. At appropriate conditions the resistivity of 5 × 10¹⁰ − 10¹²Ω cm for the anodic Al₂O₃ and the minimum density of the interface trap states of 4 × 10¹¹ cm⁻² ev⁻¹ for Al₂ O₃ -InP systems were obtained.