SiO2纳米颗粒对a-AlGaN金属-半导体-金属结构紫外探测器的影响

采用对a-AlGaN表面沉积SiO₂纳米颗粒制备工艺得到了金属-半导体-金属(MSM)结构的a-AlGaN紫外探测器。与没有沉积SiO₂纳米颗粒的探测器件相比,沉积SiO₂纳米颗粒使器件的暗电流下降了一个数量级,峰值光谱响应度提高了近3个数量级,紫外/可见抑制比大于10³。     

Au/SiO2纳米多层薄膜的制备及其性质表征

利用多靶磁控溅射技术制备了Au/SiO₂纳米颗粒分散氧化物多层复合薄膜.研究了在保持Au单层颗粒膜沉积时间一定时薄膜厚度一定、变化SiO₂的沉积时间及SiO₂的沉积时间一定而改变薄膜厚度时，多层薄膜在薄膜厚度方向的微观结构对吸收光谱的影响.研究结果表明：具有纳米层状结构的Au/SiO₂多层薄膜在560 nm波长附近有明显的表面等离子共振吸收峰，吸收峰的强度随Au颗粒的浓度增加而增强，在Au颗粒浓度相同的情况下，复合薄膜 关键词： 2纳米复合薄膜')" href="#">Au/SiO₂纳米复合薄膜 多靶磁控溅射 吸收光谱 有效介质理论     

基于HfO2插层的Ga2O3基金属-绝缘体-半导体结构日盲紫外光电探测器

作为一种新兴的超宽带隙半导体, Ga₂O₃在开发高性能的日盲紫外光电探测器方面具有独特的优势.金属-半导体-金属结构因其制备方法简单、集光面积大等优点在Ga₂O₃日盲紫外光电探测器中得到了广泛的应用.本文在传统的金属-半导体-金属结构Ga₂O₃日盲紫外光电探测器的基础上,利用原子层沉积技术引入高介电性和绝缘性的氧化铪(HfO₂)作为绝缘层和钝化层,制备出带有HfO₂插层的金属-绝缘体-半导体结构的Ga₂O₃日盲紫外光电探测器,显著降低了暗电流,提升了光暗电流比,同时提高了器件的比探测率和响应速度,为未来Ga₂O₃在高性能弱光探测器件制备提供了一种新通用策略.     

包埋Pt纳米粒子对金属-半导体-金属结构ZnO紫外光电探测器性能的影响

利用射频磁控溅射设备制备ZnO薄膜, 最终制备ZnO/Pt纳米粒子/ZnO 结构的金属-半导体-金属型紫外光电探测器. 研究了Pt纳米粒子处在ZnO薄膜层中的不同深度对金属-半导体-金属型紫外光电探测器响应性能的影响. 结果表明, 探测器的响应度随着Pt纳米粒子在ZnO薄膜层中所处深度的增大而升高. 在60 V偏压下, 包埋Pt最深的探测器在波长365 nm处取得响应度最大值1.4 A·W^-1, 包埋有Pt探测器的响应度最大值为无Pt 纳米粒子探测器响应度最大值的7倍. 结合对ZnO薄膜表面的表征及探测器各项性能的测试, 得出包埋Pt纳米粒子增强器件的响应性能可归因于表面等离子体增强散射.     

GaN基MIS紫外探测器的电学及光电特性

制备了GaN基金属-绝缘层-半导体(MIS)结构紫外探测器,并测量了其暗电流和光谱响应。通过分析其暗电流,发现在反偏情况下,其主要电流输运机制为隧穿复合机制;在正偏情况下,随着偏压的增大,电流输运机制从隧穿机制变为空间电荷限制电流机制。光谱响应测试结果显示,该探测器在-5 V的偏压下,在315 nm处获得了最大响应度170 mA/W,探测度为2.3×10¹² cm·Hz^1/2·W^-1。此外,还研究了不同厚度I层对器件光电压的影响,结果表明,光电压受隧穿机制与漏电流机制的共同制约。     

Au/SiO2纳米复合薄膜的微结构及光吸收特性研究

用多靶磁控溅射技术制备了Au/SiO₂纳米多层薄膜.利用透射电子显微镜以及吸 收光谱对Au/SiO₂复合薄膜的微观结构、表面形貌及光学性能进行了表征和测试 .研究结果表明：单层Au/SiO₂薄膜中Au沉积时间小于10s时，分散在SiO_{2< /sub>中的Au颗粒随Au的沉积时间的延长而增大；当沉积时间超过10s后，Au颗粒的尺寸几乎 不随沉积时间变化，但Au颗粒的形状由网络状结构变为薄膜状结构.［Au(t1关键词： 尺寸效应 纳米复合薄膜 吸收光谱 有效媒质理论}     

基于高阻ZnO薄膜的光电导型紫外探测器

本文通过射频磁控溅射法在玻璃衬底上沉积一层ZnO薄膜, 制备了Al-ZnO-Al 结构光电导型紫外探测器件, 并在室温下测试了所制备器件的暗场特性及其对紫外线的响应特性. 暗场条件下器件电流特性测试结果表明所制备的ZnO薄膜电阻率达到了3.71×10⁹ Ω · cm, 是一种高阻薄膜. 在波长365 nm, 光强303 μW/cm²的紫外线照射下, 薄膜的电阻率为7.20×10⁶ Ω · cm, 探测器明暗电流比达到了516. 40 V偏置电压条件下周期性开关紫外线照时, 探测器的上升和下降时间分别为199 ms和217 ms, 响应速度快且重复性好, 并利用ZnO半导体表面复合慢过程和体复合快过程对瞬态响应过程进行了理论拟合分析. 本文研究结果表明, 高阻ZnO薄膜紫外探测器具有良好的紫外光电响应特性.     

2018年2期电子期刊

光诱导功能退化是胶体量子点在应用中面临的主要挑战之一,本文针对这一问题研究了使用磁控溅射沉积SiO₂薄膜形成钝化层来提高CdSe/ZnS量子点发光稳定性的方法。首先,通过三正辛基膦辅助连续离子层吸附反应方法合成了615 nm发光的红色CdSe/ZnS量子点。然后将量子点旋涂在SiO₂/Si基片上,再通过磁控溅射方法在量子点上沉积了厚度为20 nm的SiO₂薄膜作为钝化层。使用连续波激光光源分别在空气气氛和真空条件下照射样品,研究了经过不同照射时间后钝化和未钝化量子点的稳态光致发光光谱。结果表明,随着照射时间的延长,没有SiO₂钝化的量子点的PL强度显著降低、PL峰值发生蓝移、FWHM不断增大。对比研究发现,由于SiO₂薄膜能够阻挡空气中的水和氧,减缓了量子点表面的光诱导氧化现象,因此显著提高了CdSe/ZnS量子点的稳定性。     

纳米VO2/ZnO复合薄膜的热致变色特性研究

为提高VO₂薄膜的热致变色性能,采用纳米结构和复合结构二者相结合的方法,通过磁控溅射技术先在玻璃衬底上制备高(002)取向ZnO薄膜,再在ZnO层上室温沉积钒金属薄膜,最后经热氧化处理获得纳米结构VO₂/ZnO复合薄膜.利用变温拉曼光谱观察分析了VO₂/ZnO薄膜相变前后的晶格畸变和键态的演变过程,讨论了薄膜的结构与热致红外开关特性和相变温度的内在关系.结果显示,与相同条件获得的同厚度的单层VO₂薄膜相比,纳米VO关键词： ZnO 2')" href="#">VO₂ 纳米复合薄膜 热致变色 拉曼光谱     

超亲水性SiO2-TiO2纳米颗粒阵列结构的制备与性能研究

用分子自组装的方法在玻璃衬底上分别制备了TiO₂纳米颗粒层和SiO₂-TiO₂复合纳米颗粒阵列结构. 其中,SiO₂ 纳米颗粒层用旋涂法制备,得到密排阵列结构,而TiO₂纳米颗粒层则用浸渍提拉法制备. 文章分析了TiO₂纳米颗粒层和SiO₂-TiO₂复合纳米颗粒阵列结构的理论粗糙度,并通过扫描电子显微镜研究了它们的微观结构,用接触角 关键词： 自清洁 表面粗糙度 光催化 分子自组装     

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.     

Reversible H2 passivation of Si ≡ Si3 interface defects in (1 1 1)Si/SiO2

K-band electron spin resonance (ESR) at 4.3 K has revealed the dipole-dipole (DD) interaction effects between [1 1 1]P_b centers (^*Si ≡ Si₃ defects with unpaired sp³ hybrid [1 1 1]) at the 2 dimensional (1 1 1)Si/SiO₂ interface. This has been enabled by the perfectly reversible H₂ passivation of P_b, which affects the defect's spin state. Sequential hydrogenation at 253–353°C and degassing treatments in high vacuum at 743–835°C allowed to vary the P_b density in the range 5 × 10¹⁰ < [P_b] (1.14 ± 0.06) × 10¹³ cm^-2. With increasing [P_b] fine structure doublets are clearly resolved. It is found that (1 1 1)Si/SiO₂ interfaces, dry thermally grown at ≈920°C, naturally comprise a ^*Si ≡ Si₃ defect density — passivated or not — of 1.14 × 10¹³ cm^-2.     

Dielectrics for passivation of planar InP/InGaAs diodes

We have investigated dielectrics for passivating planar InP or InGaAs photodiodes: thermally evaporated Al₂O₃ and SiO, sputtered Si₃N₄ and SiO₂ and also SiO₂ using chemical vapour deposition. The measured bulk and field-effect properties of all dielectrics excluding sputtered SiO₂ were suitable for this application. In planar InGaAs diodes with Cd diffused or Mg implanted p⁺-region a disordered dielectric/semiconductor surface led to high reverse current densities above 1 mA/cm². In InP diodes with p⁺-diffusion and dielectrics exhibiting positive flatband voltages, e.g. Si₃N₄ and Al₂O₃, reverse current densities of 10 μA/cm² were measured probably caused by a slight inversion of the semiconductor surface. With a SiO or CVD-SiO₂ passivating layer on n-InP lowest leakage current densities (10 nA/cm²) were achieved. Very low dark-current planar photodiodes InP/InGaAsP/InGaAs have been fabricated using SiO passivation (30 nA/cm²).     

利用纳米球提高红外波长上转换探测器效率

在红外波长上转换探测器氮化硅(SiN_x)钝化层制作单层六角密排的二氧化硅(SiO_2)纳米球阵列,以提高红外波长上转换探测器的整体效率.采用自组装的方法在器件钝化层上制备了直径分别约为300,450,750和1000 nm的SiO_2纳米球,并与无表面微纳结构器件进行对比测试.结果表明:钝化层附着SiO_2纳米球能有效地提高红外波长上转换器的光提取效率;当SiO_2纳米球直径为750 nm时的光提取效率最优,是无表面微纳结构器件的2.6倍,可实现低成本制作高效率红外波长上转换探测器.     

Etching mask optimization of InAs/GaSb superlattice mid-wavelength infared 640×512 focal plane array

In this paper we focused on the mask technology of inductively coupled plasma(ICP) etching for the mesa fabrication of infrared focal plane arrays(FPA).By using the SiO_2 mask,the mesa has higher graphics transfer accuracy and creates less micro-ripples in sidewalls.Comparing the IV characterization of detectors by using two different masks,the detector using the SiO_2 hard mask has the R_0A of 9.7×10~6 Ω·cm~2,while the detector using the photoresist mask has the R_0A of3.2 × 10~2 Ω·cm~2 in 77 K.After that we focused on the method of removing the remaining SiO_2 after mesa etching.The dry ICP etching and chemical buffer oxide etcher(BOE) based on HF and NH4 F are used in this part.Detectors using BOE only have closer R_0A to that using the combining method,but it leads to gaps on mesas because of the corrosion on AlSb layer by BOE.We finally choose the combining method and fabricated the 640×512 FPA.The FPA with cutoff wavelength of 4.8 μm has the average R_0A of 6.13 × 10~9 Ω·cm~2 and the average detectivity of 4.51 × 10~9 cm·Hz~(1/2).W~(-1)at 77 K.The FPA has good uniformity with the bad dots rate of 1.21%and the noise equivalent temperature difference(NEDT) of 22.9 mK operating at 77 K.     

Dramatic reduction in dark current of β-Ga2O3 ultraviolet photodectors via β-(Al0.25Ga0.75)2O3 surface passivation

Solar-blind ultraviolet photodetectors with metal-semiconductor-metal structure were fabricated based on β -(Al_0.25Ga_0.75)₂O₃/β -Ga₂O₃ film grown by metal-organic chemical vapor deposition. It was known that various surface states increase dark current and a large number of defects can hinder the transport of carriers, resulting in low switching ratio and low responsivity of the device. In this work, β -(Al_0.25Ga_0.75)₂O₃ films are used as surface passivation materials. Owning to its wide band gap, we obtain excellent light transmission and high lattice matching with β -Ga₂O₃. We explore the change and mechanism of the detection performance of the β -Ga₂O₃ detector after β -(Al_0.25Ga_0.75)₂O₃ surface passivation. It is found that under the illumination with 254 nm light at bias 5 V, the β -(Al_0.25Ga_0.75)₂O₃/β -Ga₂O₃ photodetectors show dark current of just 18 pA and high current on/off ratio of 2.16×10⁵. The dark current is sharply reduced about 50 times after passivation of the β -Ga₂O₃ surface, and current on/off ratio increases by approximately 2 times. It is obvious that β -Ga₂O₃ detectors with β -(Al_0.25Ga_0.75)₂O₃ surface passivation can offer superior detector performance.     

A new method to determine Si/SiO2 interface recombination parameters using a gate-controlled point-junction diode under illumination

A new method is presented to determine Si/SiO₂ interface recombination parameters. The device employed is constituted by a polysilicon-oxide-semiconductor capacitor with a microscale central junction (a gate-controlled point-junction diode). The excess minority carriers are photo-generated rather than being injected, which results in a one-dimensional current flow normal to the Si/SiO₂interface. The minority carrier quasi-Fermi level is probed at the Si/SiO₂ interface by means of the point junction. The one-dimensionality of the current flow and the exact knowledge of the minority carrier quasi-Fermi level permit an accurate measurement of the recombination rate. The method has been applied to characterize p-type 100 Si/SiO₂ interfaces with boron dopant concentrations ranging from 2.2×10¹⁵ to 2.0×10¹⁷ cm^-3. Data analysis has been performed using a numerical scheme to find a quasi-exact solution for the current recombining at the interface. It was found that the interface recombination parameters (trap density and capture cross-sections) depend only weakly on trap energy in a wide range around midgap. The cross-section for capturing electrons (σ_n) was found to greatly exceed (by a factor of 10² to 10³) the cross-section for capturing holes (σ_p).     

Defect versus nanocrystal luminescence emitted from room temperature and hot-implanted SiO2 layers

Silicon nanocrystals have been synthesized in SiO₂ matrix using Si ion implantation. Si ions were implanted into 300-nm-thick SiO₂ films grown on crystalline Si at energies of 30–55 keV, and with doses of 5×10¹⁵, 3×10¹⁶, and 1×10¹⁷ cm⁻². Implanted samples were subsequently annealed in an N₂ ambient at 500–1100°C during various periods. Photoluminescence spectra for the sample implanted with 1×10¹⁷ cm⁻² at 55 keV show that red luminescence (750 nm) related to Si-nanocrystals clearly increases with annealing temperature and time in intensity, and that weak orange luminescence (600 nm) is observed after annealing at low temperatures of 500°C and 800°C. The luminescence around 600 nm becomes very intense when a thin SiO₂ sample is implanted at a substrate temperature of 400°C with an energy of 30 keV and a low dose of 5×10¹⁵ cm⁻². It vanishes after annealing at 800°C for 30 min. We conclude that this luminescence observed around 600 nm is caused by some radiative defects formed in Si-implanted SiO₂.     

悬空氧化铟纳米线晶体管制备与光电性能表征

一维(1D)半导体纳米线在纳米电子学和纳米光子学中表现出色。然而,纳米线晶体管的电特性对纳米线与衬底之间的相互作用非常敏感,而优化器件结构可以改善纳米线晶体管的电学和光电检测性能。本文报道了通过一步式光刻技术制造的悬浮式In₂O₃纳米线晶体管,显示出54.6 cm²V^?1s^?1的高迁移率和241.5 mVdec^?1的低亚阈值摆幅。作为紫外光电探测器,光电晶体管显示出极低的暗电流(~10?13 A)和高响应度1.6×10⁵ A?W^?1。悬浮晶体管的沟道材料的这种简单而有效的制备方法可广泛用于制造高性能微纳米器件。     

基于P掺杂SiO2为栅介质的超低压侧栅薄膜晶体管

在室温下利用等离子体增强化学气相沉积法(PECVD)制备的颗粒膜P掺杂SiO₂为栅介质, 使用磁控溅射方法利用一步掩模法制备出一种新型结构的侧栅薄膜晶体管. 由于侧栅薄膜晶体管具有独特的结构, 在射频磁控溅射过程中, 仅仅利用一块镍掩模板, 无需复杂的光刻步骤, 就可同时沉积出氧化铟锡(ITO)源、漏、栅电极和沟道, 因此, 这种方法极大地简化了制备流程, 降低了工艺成本. 实验结果表明, 在P掺杂SiO₂栅介质层与沟道层界面处形成了超大的双电层电容(8 μF/cm²), 这使得这类晶体管具有超低的工作电压1 V, 小的亚阈值摆幅82 mV/dec、高的迁移率18.35 cm²/V·s和大的开关电流比1.1×10⁶. 因此, 这种P掺杂SiO₂双电层超低压薄膜晶体管将有望应用于低能耗便携式电子产品以及新型传感器领域. 关键词： 2')" href="#">P掺杂SiO₂ 侧栅薄膜晶体管 双电层(EDL) 超低压