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碲化锑(Sb2Te3)是一种新型二维层状材料,采用“自上而下”的超声剥离法,以碲化锑粉末为原料,以N-甲基吡咯烷酮(NMP)为分散剂,首次成功制备出碲化锑量子点(Sb2Te3 QDs),并采用多种手段(SEM,TEM,AFM,XPS,XRD等)对所制备Sb2Te3 QDs的形貌和结构进行了表征,同时还采用UV-Vis、PL及PLE探究了Sb2Te3 QDs的光学性质。研究表明:所制备的Sb2Te3 QDs平均粒径为2.3 nm,平均高度为1.9 nm,颗粒大小均匀、具有良好的分散性,PL与PLE峰位有明显的红移现象,研究还发现Sb2Te3 QDs在红外波段有明显的吸收与光致发光。研究表明:超声剥离法制备Sb2Te3 QDs是切实可行的,该量子点的PL与PLE对波长具有依赖性,其在红外波段的特性表明:它有望成为一种新型的红外探测材料。 相似文献
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用磁控溅射方法在Si衬底上制备了Al掺杂Mg2Si薄膜,通过X射线衍射仪(XRD)、扫描电镜(SEM)、原子力显微镜(AFM)和分光光度计研究了掺杂含量对Mg2Si薄膜组分、表面形貌、粗糙度及光学带隙值的影响,XRD结果表明随着Al掺杂量的增加, Mg2Si衍射峰先增强后减弱. SEM及AFM的结果表明随掺杂量的增加,结晶度先增加后降低,晶粒尺寸减小,粗糙度先增加后降低.得到掺杂后薄膜间接跃迁带隙范围为0.423~0.495 eV,直接跃迁带隙范围为0.72~0.748 eV,掺杂前薄膜间接跃迁带隙和直接跃迁带隙分别为0.53 eV、0.833 eV. 相似文献
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基于第一性原理计算软件Siesta,分析了全无机钙钛矿材料CsBI3(B=Pb,Sn,Ge)的结构、电学性质和光学性质。首先,基于GGA-PBE和GGA-PBEsol方法获得稳定的材料结构。其次,基于GGA-PBE和GGA-BLYP两种密度泛函方法分析了材料的带隙,并且通过改变材料的晶格常数,模拟材料产生的应变,对比发现材料的带隙随着晶格常数的增加而增加。此外,在超胞CsPbI3中少量掺杂Ge,发现材料的带隙会缩小0.7%到3.8%。最后,从光吸收系数可以看出,CsPbI3和CsGeI3的光吸收系数都接近6×105 cm-1,但是前者的吸收峰值位于350 nm附近,后者位于410 nm附近,而CsSnI3的光吸收系数接近4.75×105 cm-1,吸收峰位于350 nm附近。 相似文献
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采用溶胶-凝胶旋涂法(Sol-Gel Spin-Coating Method)制备了Al掺杂量为3.00at%,N掺杂量分别为6.00at%,7.00at%,8.00at%和9.00at%的Al/N共掺杂TiO2薄膜样品。对样品测试的结果表明,共掺杂样品依旧保留了TiO2的基本结构,并且Al/N共掺杂样品的晶粒尺寸有不同程度的减小,使样品表面得以修饰,变得更加均匀、平整。共掺杂样品吸收边都出现了不同程度的红移,在紫外光区以及可见光区的吸光性都有所增强。N掺杂量为7.00at%时,(101)衍射峰值最大,峰型最尖锐,所得到的TiO2薄膜的光学性能最好。共掺杂后的样品与本征TiO2相比带隙值都有所减小,且最小值为2.873eV。以上结果表明Al/N共掺杂TiO2薄膜使其光学性能得到了改善。 相似文献
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非晶碳化硅薄膜的结构及其光学特性研究 总被引:1,自引:0,他引:1
采用等离子体增强化学气相沉积系统制备非晶碳化硅薄膜,通过控制反应气体中甲烷和硅烷的流量比R来调节薄膜中的碳/硅比,获得具有不同碳/硅比的薄膜结构.采用Raman、XPS以及FT-IR等技术手段对样品的结构进行表征.通过对样品吸收谱的测量,对样品的光学特性进行了研究.研究结果表明,薄膜中C-H键以及Si-C键含量的增加引起薄膜的光学带隙展宽,在R=10时薄膜的光学带隙达到2.4 eV. 相似文献
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Phase-change nonvolatile memory cell elements composed of Sb2Te3 chalcogenide have been fabricated by using the focused ion beam method. The contact size between the Sb2Te3 phase change film and electrode film in the cell element is 2826 nm2 (diameter: 60 nm). The thickness of the Sb2Te3 chalcogenide film is 40 nm. The threshold switching current of about 0.1 mA was obtained. A RESET pulse width as short as 5 ns and the SET pulse width as short as 22 ns for Sb2Te3 chalcogenide can be obtained. At least 1000 cycle times with a RESET/SET resistance ratio >30 times is achieved for Sb2Te3 chalcogenide C-RAM cell element. 相似文献
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Feifei Liao Yinyin Lin Tingao Tang Yunfeng Lai Bomy Chen 《Microelectronics Journal》2006,37(8):841-844
With the increasing requirement of high density memory technology, a new cell structure—1TR has received much attention. It consists of a single thin film transistor (TFT) with chalcogenide Ge2Sb2Te5 as the channel material. In order to evaluate the feasibility of its application in the field of non-volatile memory, we take a further step in researching on the characteristics of GST-TFT. We fabricated a back-gate GST-TFT and investigated the output and transfer characteristics of its two states. The experimental results show that gate voltage can modulate the GST channel currents in both the amorphous and the crystalline states. Based on the experiments, we can expect that this novel device can ultimately lead to a new nonvolatile memory technology with even higher storage density. 相似文献
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DRAM is the most commonly used memory due to many advantages such as high speed and easy manufacturability owing to its simple structure, but is volatile. On the other hand, flash memory is non-volatile, but has other disadvantages such as slow speed, short lifetime, and low endurance for repetitive data writing. Compared to DRAM and flash memory, PRAM (Phase-change Random Access Memory), which is a non-volatile memory using a reversible phase change between amorphous and crystalline state, has many advantages such as high speed, high sensing margin, low operating voltage, and is being pursed as a next generation memory. Being able to pattern and etch phase change memory in nanometer scale is essential for the integration of PRAM. This study uses the Nano-Imprint Lithography (NIL) for patterning the PRAM in nanometer scale which is believed to be a future lithography technology that will replace the conventional Photo Lithography. Si wafers coated with SiO2 were used as substrates, and Ge2Sb2Te5 (GST) films with the thicknesses of 100 nm were deposited by RF sputtering. Poly-benzylmethacrylate based polymer patterns were formed using NIL on the surface of GST films, and the GST films were etched using Cl2/Ar plasma in an Oxford ICP (inductively coupled plasma) etcher. 相似文献
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Chemical mechanical planarization(CMP) of amorphous Ge2Sb2Te5(a-GST) is investigated using two typical soft pads(politex REG and AT) in acidic slurry.After CMP,it is found that the removal rate(RR) of a-GST increases with an increase of runs number for both pads.However,it achieves the higher RR and better surface quality of a-GST for an AT pad.The in-situ sheet resistance(Rs) measure shows the higher Rs of a-GST polishing can be gained after CMP using both pads and the high Rs is beneficial to lower the reset current for the PCM cells. In order to find the root cause of the different RR of a-GST polishing with different pads,the surface morphology and characteristics of both new and used pads are analyzed,it shows that the AT pad has smaller porosity size and more pore counts than that of the REG pad,and thus the AT pad can transport more fresh slurry to the reaction interface between the pad and a-GST,which results in the high RR of a-GST due to enhanced chemical reaction. 相似文献
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Phase change random access memory(PCRAM) is one of the best candidates for next generation nonvolatile memory,and phase change Si2Sb2Te5 material is expected to be a promising material for PCRAM.In the fabrication of phase change random access memories,the etching process is a critical step.In this paper,the etching characteristics of Si2Sb2Te5 films were studied with a CF4/Ar gas mixture using a reactive ion etching system.We observed a monotonic decrease in etch rate with decreasing CF4 concentration,meanwhile,Ar concentration went up and smoother etched surfaces were obtained.It proves that CF4 determines the etch rate while Ar plays an important role in defining the smoothness of the etched surface and sidewall edge acuity.Compared with Ge2Sb2Te5, it is found that Si2Sb2Te5 has a greater etch rate.Etching characteristics of Si2Sb2Te5 as a function of power and pressure were also studied.The smoothest surfaces and most vertical sidewalls were achieved using a CF4/Ar gas mixture ratio of 10/40,a background pressure of 40 mTorr,and power of 200 W. 相似文献
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Reactive-ion etching of Ge2Sb2Te5 in CF4/Ar plasma for non-volatile phase-change memories 总被引:1,自引:0,他引:1
Etching of Ge2Sb2Te5 (GST) is a critical step in the fabrication of chalcogenide random access memories. In this paper, the etch characteristics of GST films were studied with a CF4/Ar gas mixture using a reactive-ion etching system. We observed a monotonic decrease in etch rate with decreasing CF4 concentration indicating its importance in defining the material removal rate. Argon, on the other hand, plays an important role in defining the smoothness of the etched surface and sidewall edge acuity. We have studied the importance of gas mixture and RF power on the quality of the etched film. The smoothest surfaces and most vertical sidewalls were achieved using a CF4/Ar gas mixture ratio of 10/40, a background pressure of 80 mTorr, and power of 200 W. 相似文献
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Undoped and doped KCl single crystals have been successfully elaborated via the Czochralski(Cz) method.The effects of dopant Sb2O3 nanocrystals on structural and optical properties were investigated by a number of techniques,including X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray(EDAX) analysis,UV-visible and photoluminescence(PL) spectrophotometers.An XRD pattern of KCl:Sb2O3 reveals that the Sb2O3 nanocrystals are in the well-crystalline orthorhombic phase.The broadening of diffraction peaks indicated the presence of a Sb2O3 semiconductor in the nanometer size regime.The shift of absorption and PL peaks is observed near 334 nm and 360 nm respectively due to the quantum confinement effect in Sb2O3 nanocrystals.Particle sizes calculated from XRD studies agree fairly well with those estimated from optical studies.An SEM image of the surface KCl:Sb2O3 single crystal shows large quasi-spherical of Sb2O3 crystallites scattered on the surface.The elemental analysis from EDAX demonstrates that the KCl:Sb2O3 single crystal is slightly rich in oxygen and a source of excessive quantities of oxygen is discussed. 相似文献
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This paper reviews material properties of chalcogenide phase change material Ge2Sb2Te5 under thermal anneal treatments. Stress evolutions of pure Ge2Sb2Te5 films and stacks of Ge2Sb2Te5 integrating with Ti adhesion layers are investigated. Segregation of Te atoms in the Ge2Sb2Te5 film to the interface drives an interaction between Ti and Te atoms and formation of Ti-Te binary phases. The irreversible phase segregation and modification of Ge2Sb2Te5 change the crystallization process, completely suppress the final transformation into otherwise stable hcp phase, and thus impact the ultimate life-cycle of such a phase change based memory cell. Since the adhesion layer is required in cell applications, the optimization of adhesion layer material and thickness may improve the life-cycles and reliability of devices. 相似文献
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氧氩流量比对RF溅射ZnO:Mg薄膜结构及光学性能的影响 总被引:3,自引:3,他引:0
利用射频(RF)磁控溅射技术,采用单质Zn靶和 MgO陶瓷靶共溅射,在O2和Ar气的混合气氛下制备了Mg掺杂ZnO(ZnO:Mg)薄膜,并通过改变O2和Ar的流量比O 2/Ar,研究了 对ZnO:Mg薄膜的物相结构、表面形貌及光学性能的影响。结果表明,室 温下O2/Ar在1∶1~3∶1 范围内制备的薄膜均为单相的ZnO(002)薄膜,薄膜具有三维(3D)的结核生长模式;沉积的 ZnO:Mg薄膜在 N2氛下200℃退火处理后,O2/Ar为3∶1制备的薄膜在380~1200nm光谱范围内具有较高的透过率,可见光区平 均透过率约为85%、最大透过率达90%;薄膜的光学带隙 Eg为3.51eV,Mg掺杂对ZnO薄膜的光学带隙具有 较为明显的调制作用;采用极值包络线法计算表明,薄膜在589.3nm 处的折射率为1.963,膜厚约285nm。 相似文献
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基于二维拓扑绝缘体Bi_2Te_3材料利用微纳工艺制备了金属-拓扑绝缘体-金属(MTM)结构的太赫兹光电探测器.器件在0. 022 THz的响应率可达2×10~3A/W,噪声等效功率(NEP)低于7. 5×10~(-15)W/Hz~(1/2),探测率D~*高于1.62×10~(11)cm·Hz~(1/2)/W;在0. 166 THz的响应率可达281. 6 A/W,NEP低于5. 18×10~(-14)W/Hz~(1/2),D~*高于2. 2×10~(10)cm·Hz~(1/2)/W;在0. 332 THz的响应率可达7. 74 A/W,NEP低于1. 75×10~(-12)W/Hz~(1/2),D~*高于6. 7×10~8cm·Hz~(1/2)/W;同时器件在太赫兹波段具有小的时间常数(7~8μs).该项工作突破了传统光子探测的带间跃迁,实现了可室温工作、高响应率、高速响应以及高灵敏度的太赫兹探测器件. 相似文献