谐振腔增强型光电探测器的角度相关特性研究

采用MBE生长In_0.3Ga_0.7As/GaAs和GaInNAs/GaAs量子阱为有源区的器件结构材料,制备出工作在1060nm及1310nm波段的谐振腔增强型光电探测器.对谐振腔增强型光电探测器的空间角度相关特性进行了实验与物理分析,改变光束入射角度,器件谐振接收波长可在大范围调变.     

氧氩比对SnO2/Ag/SnO2透明导电膜光电性能的影响

在室温及不同的氧氩比条件下,采用射频磁控溅射Ag层和直流磁控溅射SnO₂层,在载玻片衬底上制备出了SnO₂/Ag/SnO₂多层薄膜.用霍尔效应测试仪、四探针电阻测试仪和紫外-可见-近红外光谱仪等表征了薄膜的电学性质和光学性质.实验结果表明:当氧氩比为1:14时,所制得的薄膜的光电性质优良指数最大,为1.69×10^-2 Ω^-1;此时,薄膜的电阻率为9.8×10^-5 Ω·cm,方电阻为9.68 Ω/sq,在400~800 nm可见光区的平均光学透射率达85%;并且,在氧氩比为1:14时,利用射频磁控溅射Ag层和直流磁控溅射SnO₂层在PET柔性衬底上制备出了光电性质优良的柔性透明导电膜,其在可见光区的平均光学透过率达85%以上,电阻率为1.22×10^-4 Ωcm,方电阻为12.05 Ω/sq.     

光电耦合器的反应堆中子辐射效应

 选择3种典型光电耦合器开展了反应堆中子辐照实验,中子注量为3×10¹¹~5×10¹²cm^-2时,位移效应导致电流传输比下降,饱和压降提高。发光器件相同,探测器为Si PIN光电二极管的光电耦合器比探测器为Si NPN光敏晶体管的光电耦合器的初始电流传输比要小,但其抗位移损伤能力更强。探测器均为Si NPN光敏晶体管,发光器件为异质结LED要比硅两性掺杂LED的光电耦合器的电流传输比抗位移损伤能力提高2个量级;以光敏晶体管为探测器的光电耦合器,在较大的正向电流和输出负载电阻条件下工作可提高抗辐射水平。此外,光电耦合器的位移损伤存在加电退火效应。     

薄膜型超导红外(光)探测器

在高Tc GdBaCuO超导薄膜上,采用光刻技术分别制成两种不同结构的辐射、热测量器件及2×4集成阵列式微桥器件红外(光)探测器.探测器芯片安装在STD-3型红外探测器杜瓦冷指上.用黑体及波长为0.6328μm的He-Ne激光器辐照器件,系统观测各种器件的特性,其中最好的结果:在10Hz时的噪音等效功率NEP(500,10,1)=3.6×10^-12 WH_z^1/2;探测率D^*(500,10,1)=1.6×10¹⁰ cmH_z^1/2W^-1;响应率R_v=8.2×103VW^-1.另外,多元串接微桥器件出现的多台阶式的特性,可望在红外探测计量及高频方面获得重要应用.     

Ta2O5/MgF2异质结构三维光子晶体的偏振性

为了在可见及近红外波段得到具有良好带隙结构的三维光子晶体,利用传输矩阵法分析了MgF₂、Ta₂O₅ 以及Ta₂O₅/MgF₂异质结构三维光子晶体的带隙性质.结果表明：Ta₂O₅/MgF₂异质结构三维光子晶体在820~1 020 nm的近红外波段TM模式下具有不受入射光方向影响的全方位光子带隙.该结构有望用于制作近红外光波段的偏振器件.     

4,4′,4″-三(N-3-甲基苯基-N-苯基氨基)三苯胺掺杂MoOx作为空穴传输层对有机太阳电池性能的影响

通过采用4,4′,4″-三(N-3-甲基苯基-N-苯基氨基)三苯胺 (m-MTDATA)掺入MoO_x作为器件的空穴传输层来提高酞菁铜(CuPc)/C₆₀小分子 有机太阳电池的效率. 采用真空蒸镀的方法制备了一系列器件, 其中结构为铟锡氧化物 (ITO)/m-MTDATA:MoO_x(3:1)(30 nm)/CuPc(20 nm)/C₆₀(40 nm)/4,7-二苯 基-1,10-菲罗啉 (Bphen)(8 nm)/LiF(0.8 nm)/Al(100 nm)的器件, 在AM1.5 (100 mW/cm²)模拟太阳光的照射条件下, 开路电压V_oc=0.40 V, 短路电流J_sc=6.59 mA/cm², 填充因子为0.55, 光电转换效率达1.46%, 比没有空穴传输层的器件ITO/CuPc(20 nm)/C₆₀(40 nm)/Bphen(8 nm)/LiF(0.8 nm)/Al(100 nm) 光电转换效率提高了38%. 研究表明, 加入m-MTDATA:MoO_x(3:1)(30 nm)空穴传输层减小了有机层和ITO电极之间的接触电阻, 从而减小了整个器件的串联电阻, 提高了器件的光电转换效率.     

基于氧化铟锡的无结低电压薄膜晶体管

在室温下制备了基于氧化铟锡(ITO)的底栅结构无结薄膜晶体管. 源漏电极和沟道层都是同样的ITO薄膜材料,没有形成传统的源极结和漏极结, 因而极大的简化了制备流程,降低了工艺成本.使用具有大电容的双电荷层SiO₂作为栅介质, 发现当ITO沟道层的厚度降到约20 nm时, 器件的栅极电压可以很好的调控源漏电流. 这些无结薄膜晶体管具有良好的器件性能: 低工作电压(1.5 V), 小亚阈值摆幅(0.13 V/dec)、 高迁移率(21.56 cm²/V·s)和大开关电流比(1.3× 10⁶). 这些器件即使直接在大气环境中放置4个月, 器件性能也没有明显恶化:亚阈值摆幅保持为0.13 V/dec,迁移率略微下降至18.99 cm²/V·s,开关电流比依然大于10⁶.这种工作电压低、工艺简单、 性能稳定的无结低电压薄膜晶体管非常有希望应用于低能耗便携式电子产品以及新型传感器领域.     

高Tc超导薄膜约瑟夫逊结光探测研究

我们研制了具有约瑟夫逊效应的高Tc GdBa₂Cu₃O₇-薄膜双晶晶界结,对其交直流约瑟夫逊效应进行了观测,并用其进行光探测,用波长为0.6328μm的He-Ne激光器辐照双晶结结区,系统观测了双晶晶界结的光响应特性,得到的最好结果如下噪音等效功率NEP=1.9×10^-13W,归一化探测率D=53×109cmHz^1/2W^-1,响应率Rv=4.2×10⁷V/W,响应时间τ=4.35×10^-7s.     

Ag纳米线增强硒微米管/聚噻吩自驱动光电探测器性能EI北大核心CSCD

自驱动光电探测器能够满足现代光电器件对节能和轻质的需求,但复杂的工艺和较高的成本限制了其进一步发展。本文采用旋涂法将硒微米管(Se-MT)和聚噻吩(PEDOT)制备成Se-MT/PEDOT异质结,其器件在350~700 nm波长下具有良好的光响应,无偏置电压下的响应度为8 mA/W(500 nm)。为了提高器件的光响应度,利用银纳米线(Ag-NW)修饰异质结制备Se-MT/PEDOT/Ag-NW,增强异质结在紫外-可见光区的光吸收并提高器件的光电性能。与Se-MT/PEDOT器件对比,Se-MT/PEDOT/Ag-NW器件在350~700 nm波长下的光电流数值整体上升,特别是在0 V偏压500 nm光照下,器件的响应度提升至65 mA/W(增强800%),开关比增强400%达到552,上升和下降时间明显下降至15 ms和28 ms。这一结果表明Ag-NW改性有机/无机异质结的方法可以应用于高性能光电探测器的制备。     

用Z-扫描技术研究卟啉铜偶合TiO2/SiO2有机-无机材料的非线性吸收特性

应用溶胶-凝胶技术, 成功地把5,10,15,20-四(4-磺酸苯基)卟啉铜掺杂到SiO₂/TiO₂无机凝胶中, 制备成有机-无机复合材料. 采用开孔Z-扫描技术, 使用波长532 nm、脉宽7ns的YAG脉冲激光为光源, 测定了不同浓度卟啉铜掺杂的SiO₂/TiO₂凝胶Z-扫描曲线. 应用Z扫描理论对获得的曲线进行分析与理论拟合, 得到复合材料的非线性吸收系数. 这些非线性吸收是由材料中卟啉铜的单聚体与二聚体的反饱和吸收所引起. 研究表明, 随着掺杂浓度的增大, 复合材料的非线性吸收明显增强. 掺杂浓度为1.11×10^-4 (A2), 1.48×10^-4 (A3)与3.01×10^-4 mol/L (A4)凝胶的非线性吸收系数分别为1.705×10^-11, 1.892×10^-11和4.854×10^-11 m/W. 讨论了单聚体与二聚体的浓度变化对非线性吸收的影响. 随着掺杂浓度的增加, 凝胶中二聚体与多聚体含量的增加, 导致非线性吸收系数的增大. 同时测定了无机材料对该光源的抗激光损伤阈值为～5 J/cm².     

Simulation of near-infrared photodiode detectors based on β-FeSi2/4H-SiC heterojunction

In this paper, we propose the near-infrared p-type β-FeSi₂/n-type 4H-SiC heterojunction photodetector with semiconducting silicide (β-FeSi₂) as the active region for the first time. Optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature. The results show that the photodetector has a good rectifying character and a good response to the near-infrared light. Interface states should be minimized to obtain a lower reverse leakage current. The response spectrum of the β-FeSi₂/4H-SiC detector, which consists of a p-type β-FeSi₂ absorption layer with a doping concentration of 1×10¹⁵ cm^-3 and a thickness of 2.5 μm, has a peak of 755 mA/W at 1.42 μm. The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi₂ side. The results illustrate that the β-FeSi₂/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.     

Fabrication and performance evaluation of ultraviolet photodetector based on organic /inorganic heterojunction

Organic/inorganic ultraviolet photodetector was fabricated using thermal evaporation technique. Organic/inorganic heterojunction based on thermally evaporated copper (II) acetylacetonate thin film of thickness 200 nm deposited on an n-type silicon substrate is introduced. I–V characteristics of the fabricated heterojunction were investigated under UV illumination of intensity 65 mW/cm². The diode parameters such as ideality factor, n, barrier height, Φ_B, and reverse saturation current, I_s, were determined using thermionic emission theory. The series resistance of the fabricated diode was determined using modified Nord's method. The estimated values of series resistance and barrier height of the diode were about 0.33 KΩ and 0.72 eV, respectively. The fabricated photodetector exhibited a responsivity and specific detectivity about 9 mA/W and 4.6 × 10⁹ Jones, respectively. The response behavior of the fabricated photodetector was analyzed through ON-OFF switching behavior. The estimated values of rise and fall time of the present architecture under UV illumination were about 199 ms and 154 ms, respectively. Finally, enhancing the photoresponsivity of the fabricated photodetector, post-deposition plasma treatment process was employed. A remarkable modification of the device performance was noticed as a result of plasma treatment. These modifications are representative in a decrease of series resistance and an increase of photoresponsivity and specific detectivity. The process of plasma treatment achieved an increment of external quantum efficiency from 5.53% to 8.34% at −3.5 V under UV illumination.     

Narrowband ultraviolet photodetector based on MgZnO and NPB heterojunction

An ultraviolet photodetector was fabricated based on Mg_0.07Zn_0.93O heterojunction. N, N'-bis (naphthalen-1-y1)-N, N'-bis(pheny) benzidine was selected as the hole transporting layer. I-V characteristic curves of the device were measured in the dark and under the illumination of 340?nm UV light with density of 1.33 mW/cm². The device showed a low dark current of about 3×10^-10 A and a high photo-dark current ratio of 1×10⁵ at -2 V bias. A narrowband photoresponse was observed from 300 to 400?nm and centered at 340?nm with a full width at half-maximum of only 30?nm. The maximum peak response is at 340?nm, which is 0.192 A/W at the bias of -1 V.     

深能级对AlGaInP/GaAs异质结双极晶体管性能的影响

用深能级瞬态光谱和光致发光(PL)方法研究了AlGaInP/GaAs异质结双极晶体管(HBT)发射区AlGaInP中的深能级.得到了两个深能级,分别为E_c-E_t1＝0.42eV和E_c-E_t2＝0.59eV,其复合截面为σ_n1＝6.27×10^-17cm²和σ_n2＝6.49×10^-20cm². 关键词：     

Photoelectric characteristics of photodetectors based on a GaAs/CuPc heterojunction

A study is made of the volt-ampere, volt-farad, and spectral characteristics of photodetectors based on an n-GaAs/p-CuPc heterojunction. When exposed to white light (E=600 W/m²) through Ag, the elements Cu/GaAs/CuPc/Ag have the following characteristics: U_xx=0.6 V; I_sc=30.2 A/m², FF=0.49. Based on this data and with allowance for the transmission factor (τ=7%), η=18%. Quantum efficiency is 0.5 el./phot. in the UV-region at λ₁ = 300 nm, while α₂ = 0.85 el./phot. in the visible region at λ₂ = 800 nm. The limiting sensitivity of the photodetector is 10⁻¹¹ W. The following was determined from the volt-farad and spectral characteristics: C_b=8.6·10⁻⁴ F/m²; barrier width w₁=16nm in CuPc and w₂=34 nm in CaAs; exciton diffusion length L₁=2.5 nm and L₂=7.5 nm, respectively. The photodetectors undergo almost no degradation. The values of U_xx and I_sc remain constant with multiple exposures to UV-light of 140 W/m² intensity over 6 h at constant temperature. The sensitivity region of the photodetectors is from 200 to 1000 nm. It is found that an anisotropic heterojunction in the form of two series-connected Schottky barriers is created at the boundary between n-GaAs and oxygen-doped p-CuPc in the presence of charged surface states at the interface. Vologda Polytechnic Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 41–45, July, 1996.     

Electrical characteristics of GaAs MOS capacitor and field effect transistor with atomic layer-deposited TiO2/Al2O3 dielectrics

The (NH₄)₂S treatment can reduce native oxides and passivate GaAs. Atomic layer-deposited Al₂O₃ can further remove the residue native oxides by self-cleaning. Stacked with high dielectric constant TiO₂ prepared by atomic layer deposition on Al₂O₃/(NH₄)₂S-treated GaAs MOS capacitor, the leakage current densities can reach 4.5 × 10^?8 and 3.4 × 10^?6 A/cm² at ±2 MV/cm. The net effective dielectric constant of the entire stack is 18 and the interface state density is about 4.2 × 10¹¹/cm²/eV. The fabricated enhancement-mode n-channel GaAs MOSFET exhibited good electrical characteristics with a maximum g _m of 122 mS/mm and electron mobility of 226 cm²/V s.     

Single-longitudinal mode, monolithic, green solid-state laser

We present the practical realization of a monolithic single-frequency diode pumped Nd:YVO₄/YVO₄/KTP microchip laser with birefringent filter operating at 532?nm. Theoretical analysis of the single-mode operation of such a laser configuration is presented. Experimental results are in good agreement with theoretical analysis. The laser operated with output power up to 90?mW at 532?nm. The total optical efficiency (808?nm to 532?nm) was 9.5%. Power stability was at the level of ±0.75% and the long-term frequency stability was approximately 3×10^?8. The beam has a Gaussian profile and the M2 parameter was below 1.2.     

Electrical,optical and spectral characteristics of type-II ZnSe/ZnTe/GaAs superlattice and MSM-photodetector on their base

We report on growth, fabrication and characterization of the metal–semiconductor–metal (MSM) photodiode based on type-II ZnSe/ZnTe heterostructure. Heterostructure was grown on semi-insulating GaAs substrates by MOVPE. For the first time we present the results of experimental investigations of the MSM photodetector on the base of type-II ZnSe/ZnTe superlattice. The MSM-photodetector demonstrates very low dark current, high current sensitivity and external quantum efficiency. The maximum photoresponse of the MSM-detector at the wavelength 620 nm corresponds to current sensitivity 0.22 A/W and external quantum efficiency 44%. Photoresponse of the MSM-detector shows two peaks of response located at 620 nm and 870 nm. ZnSe/ZnTe type-II superlattice structure reduces the MSM-diode dark current significantly. For the MSM-diode with finger width and gap of 3 µm and 100?×?100 µm² photosensitive area we have obtained dark current density 10^?8 A/cm² at room temperature.     

Photovoltaic characterization of n-CdTe/p-CdMnTe/GaAs diluted magnetic diode

A CdTe/CdMnTe heterojunction magnetic diode for photovoltaic applications was fabricated by using molecular beam epitaxy (MBE). The ideality factor and the potential barrier height of the diode were determined to be 1.25 and 0.836 eV, respectively. Photovoltaic parameters of the studied device were determined at various illumination intensities. The highest open circuit voltage of the CdTe/CdMnTe heterostructure was equal to 0.56 V at the illumination intensity of 130 mW/cm². The reverse current of the n-CdTe/p-CdMnTe/GaAs diode increases with the increasing illumination intensities. The obtained results suggest that n-CdTe/p-CdMnTe/GaAs diode can be used as a photodiode in photovoltaic and photodetector applications.     

A self-powered β-Ga2O3/CsCu2I3 heterojunction photodiode responding to deep ultraviolet irradiation

In this paper, a lead-free halide perovskite CsCu₂I₃ film with high stability was prepared by the anti-solvent assisted crystallization method. Then, we coupled it with Ga₂O₃ to prepare a corresponding heterojunction deep ultraviolet (UV) photodetector. After testing, we concluded that the photodetector is sensitive to 254 nm UV light. The photodetector has good reproducibility, and has an ultra-high photo-to-dark current ratio (PDCR) of more than 10⁵. In addition, under a bias of 10 V and an illuminated intensity of 200 μW/cm², the responsivity (R) and specific detectivity (D*) reached 20 mA/W and 10⁷ cm Hz^1/2 W⁻¹ (Jones), and the external quantum efficiency (EQE) is 10%. Meanwhile, the prepared photodetector could operate at zero bias, i.e., self-powered operation, along with a photocurrent of about 1 nA under illumination with UV light intensity of 200 μW/cm².