基于窄带隙聚合物的高性能可见-近红外光伏探测器

聚合物光伏探测器是一种极具应用前景的新型光电探测器件.研究了基于窄带隙聚合物的高性能可见-近红外光伏探测器,结果表明,所制备的光伏探测器在可见至近红外光谱范围内具有宽的光谱响应(380—960 nm)、出色的响应度(840 nm时达到380 mA/W)和归一化探测度;同时,器件在暗态反偏条件下的能级示意图揭示了器件内平均电场较低是较厚光敏层器件具有低噪声电流的主要原因.电容-电压与时间周期性响应曲线研究表明聚合物光伏探测器具有快速的响应能力和良好的周期重复性.     

A broadband self-powered UV photodetector of aβ-Ga2O3/γ-CuI p–n junction

The symmetric Ti/Au bi-layer point electrodes have been successfully patterned on theβ-Ga;O;films which are prepared by metal–organic chemical vapor deposition(MOCVD)and theγ-Cu I films which are prepared by spin-coating.The fabricated heterojunction has a large open circuit voltage(Voc)of 0.69 V,desired for achieving self-powered operation of a photodetector.Irradiated by 254-nm ultraviolet(UV)light,when the bias voltage is-5 V,the dark current(Idark)of the device is 0.47 p A,the photocurrent(Iphoto)is-50.93 n A,and the photo-to-dark current ratio(Iphoto/Idark)reaches about 1.08×10;.The device has a stable and fast response speed in different wavelengths,the rise time(τr)and decay time(τd)are 0.762 s and 1.741 s under 254-nm UV light illumination,respectively.While theτr andτd are 10.709 s and7.241 s under 365-nm UV light illumination,respectively.The time-dependent(I–t)response(photocurrent in the order of10-10 A)can be clearly distinguished at a small light intensity of 1μW·cm;.The internal physical mechanism affecting the device performances is discussed by the band diagram and charge carrier transfer theory.     

Atomic-layer-deposited Al_2O_3 and HfO_2 on InAlAs: A comparative study of interfacial and electrical characteristics

Al_2O_3 and HfO_2 thin films are separately deposited on n-type InAlAs epitaxial layers by using atomic layer deposition(ALD).The interfacial properties are revealed by angle-resolved x-ray photoelectron spectroscopy(AR-XPS).It is demonstrated that the Al_2O_3 layer can reduce interfacial oxidation and trap charge formation.The gate leakage current densities are 1.37×10~6 A/cm~2 and 3.22×10~6 A/cm~2 at+1V for the Al_2O_3/InAlAs and HfO_2/InAlAs MOS capacitors respectively.Compared with the HfO_2/InAlAs metal-oxide-semiconductor(MOS) capacitor,the Al_2O_3/InAlAS MOS capacitor exhibits good electrical properties in reducing gate leakage current,narrowing down the hysteresis loop,shrinking stretch-out of the C-V characteristics,and significantly reducing the oxide trapped charge(Q_(ot)) value and the interface state density(D_(it)).     

电离辐射对部分耗尽绝缘体上硅器件低频噪声特性的影响

本文针对辐射前后部分耗尽结构绝缘体上硅(SOI)器件的电学特性与低频噪声特性开展试验研究. 受辐射诱生埋氧化层固定电荷与界面态的影响, 当辐射总剂量达到1 M rad(Si) (1 rad = 10^-2 Gy)条件下, SOI器件背栅阈值电压从44.72 V 减小至12.88 V、表面电子有效迁移率从473.7 cm²/V·s降低至419.8 cm²/V· s、亚阈斜率从2.47 V/dec增加至3.93 V/dec; 基于辐射前后亚阈斜率及阈值电压的变化, 可提取得到辐射诱生界面态与氧化层固定电荷密度分别为5.33×10¹¹ cm^{- 2}与2.36×10¹² cm^-2. 受辐射在埋氧化层-硅界面处诱生边界陷阱、氧化层固定电荷与界面态的影响, 辐射后埋氧化层-硅界面处电子被陷阱俘获/释放的行为加剧, 造成SOI 器件背栅平带电压噪声功率谱密度由7×10^{- 10} V²·Hz^-1增加至1.8×10^-9 V² ·Hz^-1; 基于载流子数随机涨落模型可提取得到辐射前后SOI器件埋氧化层界面附近缺陷态密度之和约为1.42×10¹⁷ cm^-3·eV^-1和3.66×10¹⁷ cm^-3·eV^-1. 考虑隧穿削弱因子、隧穿距离与时间常数之间关系, 本文计算得到辐射前后埋氧化层内陷阱电荷密度随空间分布的变化.     

LaTiO高k栅介质Ge MOS电容电特性及Ti含量优化

采用共反应溅射法将Ti添加到La_2O_3中,制备了LaTiO/Ge金属-氧化物-半导体电容,并就Ti含量对器件电特性的影响进行了仔细研究.由于Ti-基氧化物具有极高的介电常数,LaTiO栅介质能够获得高k值;然而由于界面/近界面缺陷随着Ti含量的升高而增加,添加Ti使界面质量恶化,进而使栅极漏电流增大、器件可靠性降低.因此,为了在器件电特性之间实现协调,对Ti含量进行优化显得尤为重要.就所研究的Ti/La_2O_3比率而言,18.4%的Ti/La_2O_3比率最合适.该比率导致器件呈现出高k值(22.7)、低D_(it)(5.5×10~(11)eV~(-1)·cm~(-2))、可接受的J_g(V_g=1V,J_g=7.1×10~(-3)A·cm~(-2))和良好的器件可靠性.     

Infrared absorbance cross-sections for dinitrogen pentoxide vapour

Laboratory measurements of the ν₁₂ absorption band of gaseous N₂O₅ have been made using Fourier transform infrared (FTIR) spectroscopy at seven different temperatures between 233 and 293 K. Integrated band strengths and absorbance cross-sections per molecule show no significant temperature dependence. Their average values are S_int = (4.09±0.17) × 10^-17 cm molecule ^-1 and σ_peak = (1.90±0.08) × 10^-18 cm² molecule^-1.     

Er3+/Yb3+共掺锗碲酸盐玻璃的光谱性质及Judd-Ofelt理论分析

用高温熔融法制备了一种Er³⁺/Yb³⁺共掺的70TeO₂-5Li₂O-10B₂O₃-15GeO₂玻璃,测试和分析了其热稳定性、吸收光谱、荧光光谱以及红外吸收谱。应用Judd-Ofelt理论计算了玻璃中Er³⁺的强度参数、自发辐射跃迁几率、辐射寿命以及荧光分支比,同时比较了OH^-的存在对玻璃发光特性的影响。结果表明:这种玻璃具有较好的热稳定性,较宽的荧光半峰全宽和较大的受激发射截面,是一种较为合适的宽带光纤放大器的基质材料,OH^-的存在使得Er³⁺离子的荧光强度降低,荧光寿命减小。     

氧化铟/聚(3,4-乙烯二氧噻吩)复合材料的微结构及其热电性能研究

通过化学氧化合成的方法将纳米In_2O_3复合到聚(3,4-乙烯二氧噻吩)(PEDOT)中得到In_2O_3/PEDOT复合材料.利用X射线衍射、红外光谱、电子显微镜及正电子湮没等方法对复合材料的微观结构进行了系统研究,同时对材料的热学和电学性能进行了表征.结果表明,当In_2O_3的含量在22 wt%以下时,In_2O_3能很好地分散到PEDOT基体中.热电性能测试则显示In_2O_3/PEDOT复合材料的导电率随In_2O_3含量增加明显增大.纯PEDOT的电导率仅为7.5 S/m,而含12.3 wt%In_2O_3的复合材料的电导率达到25.75 S/m.该复合材料相应的功率因子(68.8×10~(-4)μW/m·K~2)相对于纯的PEDOT(14.5×10~(-4)μW/m·K~2)提高了近4倍.另外,复合材料的热导率相对于纯PEDOT也有所降低.最终复合材料的热电优值由0.015×10~(-4)提高到了0.073×10~(-4).结果表明,In_2O_3/PEDOT复合材料的热电性能相对于纯PEDOT的热电性能得到了比较明显的提高.     

薄膜厚度对射频磁控溅射β-Ga2O3薄膜光电性能的影响

本文在室温下利用射频磁控溅射技术在(001)蓝宝石衬底上制备了不同厚度的β-Ga₂O₃薄膜,随后将其置于氩气气氛中800℃退火1 h.利用XRD,SEM,UV-Vis分光光度计、PL光致发光光谱仪和Keithley 4200-SCS半导体表征系统等考察薄膜厚度对所得氧化镓薄膜相组成、表面形貌、光学性能以及光电探测性能的影响.结果表明,随着薄膜厚度的增加,薄膜结晶质量提高,840 nm薄膜最佳,1050 nm薄膜结晶质量略有降低.不同厚度β-Ga₂O₃薄膜在波长200—300 nm日盲区域内均具有明显的紫外光吸收,禁带宽度随着薄膜厚度的增加而增加.PL谱中各发光峰峰强随着薄膜厚度的增加而减小,表明氧空位及其相关缺陷受到抑制.在β-Ga₂O₃薄膜基础上制备出日盲紫外光电探测器的探测性能(光暗电流比,响应度,探测率,外量子效率)也随薄膜厚度的增加呈先增后减的趋势.厚度约为840 nm的β-Ga₂O₃紫外光电探测器,在5...     

LaTiON/LaON as band-engineered charge-trapping layer for nonvolatile memory applications

Charge-trapping characteristics of stacked LaTiON/LaON film were investigated based on Al/Al₂O₃/LaTiON-LaON/SiO₂/Si (band-engineered MONOS) capacitors. The physical properties of the high-k films were analyzed by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The band profile of this band-engineered MONOS device was characterized by investigating the current-conduction mechanism. By adopting stacked LaTiON/LaON film instead of LaON film as charge-trapping layer, improved electrical properties can be achieved in terms of larger memory window (5.4 V at ±10-V sweeping voltage), higher program speed with lower operating gate voltage (2.1 V at 100-μs +6 V), and smaller charge loss rate at 125 °C, mainly due to the variable tunneling path of charge carriers under program/erase and retention modes (realized by the band-engineered charge-trapping layer), high trap density of LaTiON, and large barrier height at LaTiON/SiO₂ (2.3 eV).     

负电荷层对a-IGZO TFT阈值电压的影响

采用脉冲直流磁控溅射的方式沉积In-Ga-Zn-O (IGZO)膜层作为TFT的有源层.在TFT沟道处的有源层和绝缘层的界面上, 通过溅射法制作一定厚度的负电荷层对阈值电压(V_th)进行调制, 使得V_th由-3.8 V升高至-0.3 V, 器件由耗尽型向增强型转变.通过增加Al₂O₃作为负电荷层, 可有效地将V_th控制在0 V附近, 并且提高其器件稳定性, 得到较好的电学特性:电流开关比I_on/I_off>10⁹, 亚阈值摆幅SS为0.2 V/dec, 阈值电压V_th为-0.3 V, 迁移率μ为9.2 cm² /(V·s).     

Local microstructural analysis for Y_2O_3/Eu~(3+)/Mg~(2+) nanorods by Raman and photoluminescence spectra under high pressure

In this paper, we investigate the Raman and photoluminescence spectra of Y_2O_3/Eu~(3+) and Y_2O_3/Eu~(3+)/Mg~(2+) nanorods under high pressures using 514-nm and 532-nm laser light excitation. We observe transitions from the initial cubic phase to amorphous at pressures higher than 24 GPa for both Y_2O_3/Eu~(3+) and Y_2O_3/Eu~(3+)/Mg~(2+) nanorods. In addition, Y_2O_3/Eu~(3+) and Y_2O_3/Eu~(3+)/Mg~(2+) nanorods exhibit different distorted states after the pressure has been raised to 8 GPa. The analyses of intensity ratios, I_(0-2)/I_(0-1) from ~5D_(0–)~7F2_to~5D_(0–)~7F_1and I_(0-2)A/B of ~5D_(0–)7F_2 transitions indicate that Y_2O_3/Eu~(3+)/Mg~(2+) nanorods exhibit stronger local micro-surrounding characteristics for Eu~(3+) ions in a pressuremodulated crystal field. The doped Mg2+ion results in reducing the crystal ionicity in the distorted lattice state under high pressures. The use of doped ions as an ion modifier can be applied to the study of small local microstructural changes through Eu~(3+) luminescence.     

Effect of exchange coupling on magnetic property in Sm–Co/α-Fe layered system

The hysteresis loops as well as the spin distributions of Sm–Co/α-Fe bilayers have been investigated by both threedimensional(3D) and one-dimensional(1D) micromagnetic calculations, focusing on the effect of the interface exchange coupling under various soft layer thicknesses t~s. The exchange coupling coefficient Ahsbetween the hard and soft layers varies from 1.8 × 10~(-6)erg/cm to 0.45 × 10~(-6)erg/cm, while the soft layer thickness increases from 2 nm to 10 nm. As the exchange coupling decreases, the squareness of the loop gradually deteriorates, both pinning and coercive fields rise up monotonically, and the nucleation field goes down. On the other hand, an increment of the soft layer thickness leads to a significant drop of the nucleation field, the deterioration of the hysteresis loop squareness, and an increase of the remanence. The simulated loops based on the 3D and 1D methods are consistent with each other and in good agreement with the measured loops for Sm–Co/α-Fe multilayers.     

高Yb3+/Er3+掺杂的磷基有源光纤材料的光谱性质

研究了Yb³⁺/Er³⁺共掺60P₂O₅-15BaO-10Al₂O₃-5ZnO-10R₂O（R=Na,K）以P₂O₅为主体的磷基有源光纤材料的光谱性质,以及不同Yb³⁺/Er³⁺掺杂浓度对光谱性质的影响规律。当Er³⁺浓度为9.100×10¹⁹/cm³、Yb³⁺的掺杂浓度为5.407×10²⁰/cm³、Yb³⁺/Er³⁺浓度比为6：1时,玻璃样品在1 531 nm处的受激发射截面最大,为6.17×10^-21 cm²。同时,其荧光寿命为9.73 ms,荧光半高宽为53.16 nm,发射截面与半高宽的乘积为3.28×10^-32 m³,综合性能最佳。     

Influence of the transparency of tunnel barriers in Nb/Al2O3/Al/Al2O3/Nb junctions on transport properties

The transparency of the tunnel barriers in double-barrier junctions influences the critical current density and the form of the current–voltage characteristics (IVC). Moreover, the barrier asymmetry is an important parameter, which has to be controlled in the technological process. We have performed a systematic study of the influence of the barrier transparency on critical current, I_C, and normal resistance, R_N, by preparing SIS and SINIS junctions under identical technological conditions and comparing their transport properties. We have fabricated Nb/Al₂O₃/Nb and Nb/Al₂O₃/Al/Al₂O₃/Nb devices with different current densities using a conventional fabrication process, varying pressure and oxidation time. The thickness of the Al middle electrode in all Nb/Al₂O₃/Al/Al₂O₃/Nb junctions was 6 nm. Patterning of the multilayers was done using conventional photolithography and the selective niobium etching process. The current density of SIS junctions was changed in the range from 0.5 to 10 kA/cm². At the same conditions the current density of SINIS devices revealed 1–100 A/cm² with non-hysteretic IVC and characteristic voltages, I_CR_N, of up to 200 μV. By comparing the experimental and theoretical temperature dependence of the I_CR_N product we estimated the barrier transparency and its asymmetry. The comparison shows a good agreement of experimental data with the theoretical model of tunneling through double-barrier structures in the dirty limit and provides the effective barrier transparency parameter γ_eff≈300. A theoretical framework is developed to study the influence of the barrier asymmetry on the current–phase relationship and it is proposed to determine the asymmetry parameter by measuring the critical current suppression as function of applied microwave power. The theoretical approach to determine the non-stationary properties of double-barrier junctions in the adiabatic regime is formulated and the results of calculations of the I–V characteristics are given in relevant limits. The existence and the magnitude of a current deficit are predicted as function of the barrier asymmetry.     

掺Er3+碲酸盐玻璃的光谱性质与Judd-Ofelt理论分析

用高温熔融法制备了碲酸盐玻璃(70TeO₂-9B₂O₃-6Nb₂O₅-5Na₂O-10ZnO-1%(质量分数)Er₂O₃)样品。测试了玻璃样品的吸收光谱和荧光光谱。应用Judd-Ofelt理论计算了Er³⁺离子的谱线强度、自发辐射跃迁几率、荧光分支比、辐射寿命等光谱参数,并拟合了相应的强度参数Ω_t(t=2,4,6)(Ω₂=8.01×10^-20cm²,Ω₄=2.09×10^-20cm²,Ω₆=1.15×10^-20cm²)。结果发现该碲酸盐玻璃具有较大的Ω₂值,说明Er—O键的共价性强于它在硅酸盐、锗酸盐、氟化物、铋酸盐和磷酸盐玻璃中的共价性。Er³⁺在碲酸盐玻璃中⁴I_13/2→⁴I_15/2跃迁几率约为492s^-1,表明Er³⁺可能有较强的1.5μm发射。分析了Er³⁺在碲酸盐玻璃中能级⁴I_13/2→⁴I_15/2发射的荧光半峰全宽(FWHM=73nm),并应用McCumber理论计算了Er³⁺的受激发射截面(σ_e=1.08×10^-20cm²),发现其FWHM×σ_e远大于Er³⁺在铋酸盐、磷酸盐、锗酸盐和硅酸盐玻璃中的受激发射截面,说明碲酸盐玻璃是一种制备宽带光纤放大器的优良基质材料。     

基于电场调控的高性能紫外无机-有机复合结构光电探测器

通过溶液旋涂制备了结构为ITO/ZnO/P3HT:ITIC/Ag的紫外无机-有机复合结构光电探测器,混合膜中聚合物给体(P3HT)和非富勒烯小分子受体(ITIC)的质量比为100:1.由于载流子传输通道不连续,器件在零偏压下的暗电流密度很小,为5.8×10-10 A·cm-2,为器件实现外加电场可调和光电流倍增提供了条...     

溅射相关的Pb97.4Sn2.6合金表面现象研究

本文对Pb_97.4Sn_2.6合金表面在溅射时所产生的一些现象进行了研究。实验在室温下,利用PHI-590型扫描俄歇微探针进行。根据理论计算结果对实验数据进行分析后,观察到了溅射增强扩散效应。当Ar⁺离子能量为5千电子伏,离子流密度为70微安/厘米²时,测得锡在合金中的扩散系数为10^-15厘米²/秒量级,影响层厚度约为200埃。 关键词：     

High-responsivity solar-blind photodetector based on MOCVD-grown Si-doped β-Ga_2O_3 thin film

Si-doped β-Ga_2O_3 films are fabricated through metal-organic chemical vapor deposition(MOCVD). Solar-blind ultraviolet(UV) photodetector(PD) based on the films is fabricated by standard photolithography, and the photodetection properties are investigated. The results show that the photocurrent increases to 11.2 m A under 200 μW·cm-2254 nm illumination and ±20 V bias, leading to photo-responsivity as high as 788 A·W~(-1). The Si-doped β-Ga_2O_3-based PD is promised to perform solar-blind photodetection with high performance.     

沟道层厚度对室温制备的In2O3薄膜晶体管器件性能的影响

在室温下采用直流磁控溅射以SiO₂/Si为衬底制备了不同沟道层厚度的底栅式In₂O₃薄膜晶体管,讨论了沟道层厚度对底栅In₂O₃薄膜晶体管的电学性能的影响。实验结果表明:器件的特性与沟道层厚度有关,最优沟道层厚度的In₂O₃薄膜晶体管为增强型,其阈值电压为2.5 V,开关电流比约为10⁶,场效应迁移率为6.2 cm²·V^-1·s^-1。