简易化学水浴法制备SnO_2/p-Si异质结光电性能（英文）

通过一种简易化学水浴法将SnO_2薄膜沉积在晶硅衬底上以制备n-SnO_2/p-Si异质结光电器件,这种自制的化学水浴装置非常便宜和方便.采用XRD、SEM、XPS、PL、紫外-可见光分光光度计和霍尔效应测试系统表征了SnO_2薄膜的微结构、光学和电学性能,对SnO_2/p-Si异质结的I-V曲线进行测试并分析,获得明显的光电转换特性.     

射频磁控溅射法制备AZO/p-Si异质结及其性能研究

利用射频磁控溅射法,在p-Si衬底上生长了Al掺杂的ZnO(AZO)薄膜,并进而制备了AZO/p-Si异质结。X射线衍射仪、紫外-可见光分光光度计、四探针测试仪和霍尔效应测试仪测量表明,AZO薄膜具有良好的结晶质量、光学和电学特性。暗态下的I-V测试表明,AZO/p-Si异质结具有较好的整流特性,反向饱和电流为1.29×10-6A,±2V处的正向和反向电流之比为229.41,计算得出异质结的理想因子为2.28。在标准光照下AZO/p-Si异质结呈现出明显的光生伏特效应,这种异质结太阳电池具有2.51%的光电转换效率。     

CH3NH3PbI3/p-Si异质结的光电特性研究

利用一步溶液法在p型Si衬底上生长有机/无机杂化钙钛矿CH3NH3PbI3薄膜,构成CH3NH3PbI3/p-Si异质结。利用原子力显微镜(AFM)、扫描电子显微镜(SEM)对薄膜形貌和结构进行表征,通过无光照和有光照条件下的电流-电压(I-V)、电容-电压(C-V)测试对异质结的光电特性进行研究。I-V测试结果显示CH3NH3PbI3/p-Si异质结具有整流特性,正反偏压为±5V时,整流比大于70,并在此异质结上观察到了光电转换现象,开路电压为10mV,短路电流为0.16uA。C-V测试结果显示Ag/CH3NH3PbI3/p-Si异质结具有与MIS(金属-绝缘层-半导体)结构相似的C-V特性曲线,与理想MIS的C-V特性曲线相比,异质结的C-V曲线整体沿电压轴向正电压方向平移。C-V特性曲线的这种平移表明Ag/CH3NH3PbI3/p-Si异质结界面存在界面缺陷,CH3NH3PbI3层也可能存在固定电荷。这种界面缺陷是导致CH3NH3PbI3/p-Si异质结开路电压的大幅度降低的重要原因。此外,CH3NH3PbI3薄膜的C-V测试结果显示其具有介电非线性特性,其介电常数约为4.64。     

ZnO/p-Si异质结的I-V及C-V特性研究

通过磁控溅射Al掺杂的ZnO陶瓷靶,在p-Si片上沉积n型电导的ZnO薄膜而制备了ZnO/p-Si异质结,并通过测试其光照下的I-V、C-V特性对其光电特性以及载流子输运特性与导电机理进行了研究。研究表明ZnO/p-Si异质结存在良好的整流特性与光电响应,可以广泛应用在光电探测和太阳电池等领域。由于在ZnO/p-Si异质结界面处的导带补偿与价带补偿相差太大的缘故,在正向电压超过1V时,导电机理为空间电荷限制电流导电。同时,研究表明ZnO/p-Si异质结界面存在大量界面态,可以通过减小界面态进一步提高其光电特性。     

ZnO/SiC/Si异质结的光电转换特性

我们利用直流溅射制备了一系列的n-ZnO/n-SiC/p-Si和n-ZnO/p-Si异质结,通过研究他们的结构、I-V曲线、光生伏特效应和光响应谱。并且研究了他们的光电转换特性。发现n-ZnO/n-SiC/p-Si异质结的光电转换效率大约是n-ZnO/p-Si异质结的四倍。n-ZnO/n-SiC/p-Si异质结的光响应曲线也比n-ZnO/p-Si异质结强,表明n-ZnO/p-Si异质结加入3C-SiC中间层后光响应明显增强。在表面光电流谱中n-ZnO/n-SiC/p-Si异质结观察到两个拐点,而n-ZnO/p-Si异质结只观察到一个。通过以上研究可以看出3C-SiC在n-ZnO/n-SiC/p-Si异质结的光电转换中起了很大的作用.     

p-CuAlO2/(n-, p-)Si异质结的制备与电学性质

采用化学溶液法在n型和p型Si衬底上成功制备了单相CuAlO2薄膜。薄膜的电导率-温度曲线显示,薄膜在200K-300K温度范围内呈热激活导电模式,激活能约为0.3eV。电流-电压特性测试显示,p-CuAlO2/n-Si异质结具有明显的整流特性,开启电压约为1.6V,在±3V处的整流率约为35,而p-CuAlO2/p-Si同型异质结表现出类似肖特基结的电学性质,由于p-CuAlO2导电性远低于p-Si衬底,正向电流受空间电荷限制。     

LP-MOCVD法制作n-ZnO/p-Si异质结及其电致发光研究

采用低压-金属有机化学气相沉积法(LP-MOCVD)在(100)p-Si衬底上制备未掺杂n型ZnO薄膜,并制作了相应的n-ZnO/p-Si异质结器件.通过X射线衍射(XRD)、光致发光(PL)光谱和霍尔测试分别研究了所制备薄膜的结构、光学和电学特性.得到具有较高质量的n型ZnO薄膜.在室温条件下,测得了该类异质结器件正向注入电流下可见光和近红外区域的电致发光(EL).     

Study and Fabrication of a Au/n-ZnO/p-Si Structure UV-Enhanced Phototransistor

研究和制作了一种新型Au/n-ZnO/p-Si结构的肖特基发射极、异质结集电极紫外增强双极型光电三极管.分析了器件原理,测试了I-V特性、C-V特性以及器件的光谱响应,从200到400nm的紫外光响应灵敏度得到明显增强而对大于400nm的可见光的响应特性得到保留.实验显示Au/n-ZnO/p-Si结构的紫外增强型的光电三极管对紫外光的响应明显增强,对371nm波长的紫外光的灵敏度是普通n-ZnO/p-Si异质结紫外光电二极管道的5～10倍.     

Au/n-znO/p-Si结构的紫外增强型光电三极管的研制

研究和制作了一种新型Au/n-ZnO/p-Si结构的肖特基发射极、异质结集电极紫外增强双极型光电三极管.分析了器件原理,测试了I-V特性、C-V特性以及器件的光谱响应,从200到400nm的紫外光响应灵敏度得到明显增强而对大于400nm的可见光的响应特性得到保留.实验显示Au/n-ZnO/p-Si结构的紫外增强型的光电三极管对紫外光的响应明显增强,对371nm波长的紫外光的灵敏度是普通n-ZnO/p-Si异质结紫外光电二极管道的5～10倍.     

（英）磁控溅射制备纳米晶GZO/CdS双层膜及GZO/CdS/p-Si异质结光伏器件的研究

本文中,采用磁控溅射制备Ga掺杂ZnO (GZO)/CdS双层膜在p型晶硅衬底上以形成GZO/CdS/p-Si异质结器件。纳米晶GZO/CdS双层膜的微结构、光学及电学特性,通过XRD、SEM、XPS、紫外-可见光分光光度计和霍尔效应测试系统表征。GZO/CdS/p-Si异质结J-V曲线显示良好的整流特性。在±3V时,整流比IF/IR(IF和IR分别表示正向和反向电流)已达到21。结果表明纳米晶GZO/CdS/p-Si异质结具有好的二极管特性,在反向偏压下获得高光电流密度。纳米晶GZO/CdS/p-Si异质结显示明显的光伏特性。由于CdS晶格常数在GZO和晶Si之间,它能作为一个介于GZO和晶Si之间的缓冲层,能有效地减少GZO和p-Si之间的界面态。因此,我们获得了GZO/CdS/p-Si异质结明显光伏特性。     

WO3/SnO2复合薄膜的制备及光电性能

采用水热法和电化学沉积法,成功制备了包覆有SnO₂纳米颗粒的WO₃纳米棒阵列薄膜,退火处理后形成WO₃/SnO₂异质结复合薄膜。通过改变SnO₂的沉积时间得到了复合薄膜的最佳制备条件。采用XRD,FESEM对WO₃/SnO₂复合薄膜的物相和形貌进行了分析,通过电化学工作站对WO₃/SnO₂复合薄膜的光电性能进行了研究,结果表明,电沉积时间为120 s时,WO₃/SnO₂复合薄膜具有最小的阻抗,且在0.6 V的偏压下光电流密度为0.46 mA/cm²,相比于单一WO₃纳米棒薄膜,表现出更好的光电化学性能。     

Determination of the electronic parameters of nanostructure SnO2/p-Si diode

The current–voltage and capacitance–voltage characteristics of the nanostructure SnO₂/p-Si diode have been investigated. The optical band gap and microstructure properties of the SnO₂ film were analyzed by optical absorption method and scanning electron microscopy, respectively. The optical band of the film was found to be 3.58 eV with a direct optical transition. The scanning electron microcopy results show that the SnO₂ film has the nanostructure. The ideality factor, barrier height and series resistance values of the nanostructure SnO₂/p-Si diode were found to be 2.1, 0.87 eV and 36.35 kΩ, respectively. The barrier height obtained from C–V measurement is higher than obtained from I–V measurement and this discrepancy can be explained by introducing a spatial distribution of barrier heights due to barrier height inhomogeneities, which are available at the nanostructure SnO₂/p-Si interface. The interface state density of the diode was determined by conductance technique and was found to be 8.41 × 10¹⁰ eV⁻¹ cm⁻².It is evaluated that the nanostructure of the SnO₂ film has an important effect on the ideality factor, barrier height and interface state density parameters of SnO₂/p-Si diode.     

Preparation and gas sensitivity of WO3 hollow microspheres and SnO2 doped heterojunction sensors

Dispersed tungsten trioxide (WO₃) microsphere aggregates were prepared by chemical reduction with hydrazine hydrate in a glycol–water system, and the composites of WO₃/tin oxide (SnO₂) with different SnO₂ weight fractions were prepared by microwave refluxing. The products were characterized by x-ray diffraction, field emission scanning electron microscopy, thermogravimetric-differential thermal analysis, Fourier transform infrared spectroscopy, and the Brunauer–Emmett–Teller method. The gas-sensing characteristics based on the composites were investigated by a stationary-state gas distribution method. The results show that the noncompact WO₃ microspheres with hollow structure were obtained. The phase composition and the morphology of WO₃ were changed by SnO₂ doping. The heterojunction structure was formed between WO₃ and SnO₂, and the heterojunction sensors have high sensitivity to H₂S, NO_X, and xylene at relatively lower operating temperature, especially the sensor doped by 3% SnO₂ operating just at 90 °C for H₂S gas.     

Fabrication,temperature dependent current-voltage characteristics and photoresponse properties of Au/α-PbO2/p-Si/Al heterojunction photodiode

Thin film of lead dioxide, α-PbO₂, has been grown by thermal evaporation technique on the single crystal of p-Si substrate and heterojunction photodiode, Au/α-PbO₂/p-Si/Al, was fabricated. The current-voltage characteristics of the diode have been studied in the temperature ranged from 303 to 373 K and the voltage applied during measurements varied from −1 to 1.5 V. It was found from the (I-V) characteristics of the diode that the conduction mechanisms in the forward bias direction are controlled by the thermionic emission at bias potential ≤0.7 V followed by single trap space charge limited current (SCLC) conduction in the voltage range >0.7 V. The capacitance-voltage characteristics of the device were studied at room temperature in dark condition and it has been shown that the diode is abrupt junction. The carrier concentration on both sides of the depletion layer has been determined. Energy band diagram for α-PbO₂/p-Si device was constructed. The device under illumination with light of intensity 20 W/m² gives acceptable values of photoresponse parameters such as photosensitivity and photoconductivity. The presented photodiode parameters exhibit the typical photosensor applications with reproducibility phenomenon.     

Interface Formation and Electrical Transport in SnO<Subscript>2</Subscript>:Eu<Superscript>3+</Superscript>/GaAs Heterojunction Deposited by Sol–Gel Dip-Coating and Resistive Evaporation

The natural n-type conduction of tin dioxide (SnO₂) may be compensated by trivalent rare-earth doping. In this work, SnO₂ thin films doped with Eu³⁺ have been deposited by the sol–gel dip-coating (SGDC) process, topped by a GaAs layer deposited by the resistive evaporation technique. The goal is the combination of a very efficient rare-earth emitting matrix with a high-mobility semiconductor. The x-ray diffraction pattern of SnO₂:Eu/GaAs heterojunctions showed simultaneously the crystallographic plane characteristics of GaAs as well as cassiterite SnO₂ structure. The electric resistance of the heterojunction device is much lower than the resistance of the SnO₂:2 at.%Eu and GaAs films considered separately. Micrographs obtained by scanning electron microscopy (SEM) of the cross-section showed that the interface is clearly identified, exhibiting good adherence and uniformity. A possible explanation for the low resistivity of the SnO₂:2 at.%Eu/GaAs heterojunction is the formation of small channels with two-dimensional electron gas (2DEG) behavior.     

Enhanced photovoltaic performances of the dye-sensitized solar cell by utilizing rare-earth modified tin oxide compact layer

Multifunctional and ultrathin tin oxide (SnO₂) compact layer is modified by europium ion doped ytterbium fluoride (YbF₃:Eu³⁺), which is first designed and fabricated by a facile spin-coating method for the dye-sensitized solar cell (DSSC). The device with SnO₂/YbF₃:Eu³⁺ compact layer exhibits enhanced long-term stability and photoelectric conversion efficiency (PCE) compared to those of the device without compact layer. The enhanced long-term stability is due to the SnO₂/YbF₃:Eu³⁺ compact layer can transform ultraviolet (UV) light into visible light to mitigate dye degradation. The enhanced PCE is associated with the reduced recombination rate of electrons, the enhanced short-wavelength light response, and the high transparency of the compact layer. Moreover, the novel strategy of preparation SnO₂/YbF₃:Eu³⁺ compact layer is an universal method to adjust rare-earth species to achieve up- or down-conversion functions, and the multifunctional compact layer can be widely applied in the photovoltaic device.     

Facile Fabrication of SWCNT/SnO2 Nanowire Heterojunction Devices on Flexible Polyimide Substrate

We report on the fabrication and electronic properties of single‐walled carbon nanotube (SWCNT)/tin oxide nanowire (SnO₂ NW) heterojunction device arrays on flexible polyimide (PI) substrates. Hetero‐NW junctions consisting of crossed SnO₂ NWs and SWCNTs were fabricated by sliding transfer of SnO₂ NWs onto the SWCNT channels on PI substrate. Individual SWCNTs and SnO₂ NWs field effect transistors showed p‐ and n‐type transfer properties with current on/off ratios of 7.0 × 10⁵ and 2.7 × 10⁶, respectively. The heterojunction diode showed a rectifying behavior with a rectification ratio of higher than 10³ at ±1 V and the analysis with an equivalent circuit model of serially connected diode and resistor estimated an ideality factor of 1.5 and the resistance of 20 MΩ. The rectification of AC input signal was clearly demonstrated by fabricating a full‐wave bridge circuit of heterojunctions. In addition, the heterojunctions showed a high UV photosensitivity of ～10⁴ under reverse bias, suggesting their implicit applications in UV sensors.