A simple chemical-etching approach is used to prepare the silicon carbide quantum dots (QDs). The raw materials of silicon carbide (SiC) with homogeneous nanoparticles fabricated via self-propagating combustion synthe...A simple chemical-etching approach is used to prepare the silicon carbide quantum dots (QDs). The raw materials of silicon carbide (SiC) with homogeneous nanoparticles fabricated via self-propagating combustion synthesis are corroded in mixture etchants of nitric and hydrofluoric acid. After sonication and chromatography in the ultra-gravity field for the etched products, aqueous solution with QDs can be obtained. The microstructure evolution of raw particles and optical properties of QDs were measured. Different organophilic groups on the surface like carboxyl, oxygroup, and hyfroxy were produced in the process of etching. Fluorescent labeling and imaging for living cells of Aureobasidium pulluans were investigated. The results indicated that SiC QDs were not cytotoxic and could stably label due to the conjugation between organophilic groups of QDs and specific protein of cells, it can be utilized for fluorescent imaging and tracking cells with in vivo and long-term-distance. Moreover, mechanism and specificity of mark were also analyzed.展开更多
Nowadays the development of Internet of Things （loT） and defense technologies imperatively needs high-performance photodetectors that can work in a broadband wavelength range, in particular, covering the mid-infrar...Nowadays the development of Internet of Things （loT） and defense technologies imperatively needs high-performance photodetectors that can work in a broadband wavelength range, in particular, covering the mid-infrared （MIR） region [1]. This generates great interest in the incorporation of a series of novel optoelectronic materials and structures into the photodetectors. Graphene and colloidal quantum dots （QDs） are key players among novel materials used to fabricate high-performance photodetectors [2-4]. By taking advantage of the high mobility of graphene and excellent tunable optical absorption of colloidal QDs,展开更多
The fluorescence of graphene oxide quantum dots （GOQDs） that are infiltrated into porous silicon （PSi） is investigated. By dropping activated GOQDs solution onto silanized PSi samples, GOQDs are successfully in- f...The fluorescence of graphene oxide quantum dots （GOQDs） that are infiltrated into porous silicon （PSi） is investigated. By dropping activated GOQDs solution onto silanized PSi samples, GOQDs are successfully in- filtrated into a PSi device. The results indicate that the intensity of the fluorescence of the GOQD-inflltrated multilayer with a high reflection band located at its fluorescence spectra scope is approximately double that of the single layer sample. This indicates that the multilayer GOQD-infiltrated PSi substrate is a suitable material for the preparation of sensitive photoluminescence biosensors.展开更多
采用脉冲激光烧蚀法,以多晶3C-SiC陶瓷片为靶材,制备了悬浮于去离子水中的非晶SiC纳米颗粒。利用透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、傅里叶变换红外吸收光谱(FTIR)、紫外可见吸收光谱(UV-Vis)和光致发光谱(PL)等测试...采用脉冲激光烧蚀法,以多晶3C-SiC陶瓷片为靶材,制备了悬浮于去离子水中的非晶SiC纳米颗粒。利用透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、傅里叶变换红外吸收光谱(FTIR)、紫外可见吸收光谱(UV-Vis)和光致发光谱(PL)等测试手段对其形貌、结构和光学性质进行了分析。结果表明:这些纳米颗粒由大量的非晶SiC构成,粒径在8~9 nm,光学带隙为3.28 e V;样品表现出较强的光致发光,发光峰位于415 nm处,这主要是由于量子限制效应造成的。展开更多
采用磁控共溅射沉积法,以Si靶和SiC靶为靶材,单晶Si(100)和石英为衬底,在不同衬底温度下沉积了富硅SiC_x薄膜。在氮气氛下于1100℃退火,得到包含硅量子点的SiC_x薄膜。采用傅立叶变换红外吸收光谱、拉曼光谱、掠入射X射线衍射和吸收谱...采用磁控共溅射沉积法,以Si靶和SiC靶为靶材,单晶Si(100)和石英为衬底,在不同衬底温度下沉积了富硅SiC_x薄膜。在氮气氛下于1100℃退火,得到包含硅量子点的SiC_x薄膜。采用傅立叶变换红外吸收光谱、拉曼光谱、掠入射X射线衍射和吸收谱对退火后的SiC_x薄膜进行了表征。结果表明:当衬底温度从室温(25℃)升至300℃时,薄膜的晶化率增至71.3%,硅量子点尺寸增至8.9 nm,而光学带隙则减至2.42 e ;随着衬底温度进一步升高,薄膜的晶化率降至63.1%,硅量子点尺寸减小至7.3 nm,而光学带隙却增加至2.57 e ;当衬底温度从室温(25℃)升至400℃时,薄膜的吸收系数呈先增大后减小趋势。在本实验条件下,最佳衬底温度为300℃。展开更多
The combination of SiC quantum dots sensitized inverse opal TiO_(2) photocatalyst is designed in this work and then applied in wastewater purification under simulated sunlight.From various spectroscopic techniques,it ...The combination of SiC quantum dots sensitized inverse opal TiO_(2) photocatalyst is designed in this work and then applied in wastewater purification under simulated sunlight.From various spectroscopic techniques,it is found that electrons transfer directionally from SiC quantum dots to inverse opal TiO_(2),and the energy difference between their conduction/valence bands can reduce the recombination rate of photogenerated carriers and provide a pathway with low interfacial resistance for charge transfer inside the composite.As a result,a typical type-II mechanism is proved to dominate the photoinduced charge transfer process.Meanwhile,the composite achieves excellent photocatalytic performances(the highest apparent kinetic constant of 0.037 min^(-1)),which is 6.2 times(0.006 min^(-1))and 2.1 times(0.018 min^(-1))of the bare inverse opal TiO_(2) and commercial P25 photocatalysts.Therefore,the stability and non-toxicity of SiC quantum dots sensitized inverse opal TiO_(2) composite enables it with great potential in practical photocatalytic applications.展开更多
Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent pr...Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent progress of the direct epitaxy and fabrication of quantum dot （QD） lasers and integrated guided-wave devices on silicon. This approach involves the development of molecular beam epitaxial growth of self- organized QD lasers directly on silicon substrates and their monolithic integration with amorphous silicon waveguides and quantum well electroabsorption modulators. Additionally, we report a preliminary study of long-wavelength （〉 1.3 μm） QD lasers grown on silicon and integrated crystalline silicon waveguides using membrane transfer technology.展开更多
文摘A simple chemical-etching approach is used to prepare the silicon carbide quantum dots (QDs). The raw materials of silicon carbide (SiC) with homogeneous nanoparticles fabricated via self-propagating combustion synthesis are corroded in mixture etchants of nitric and hydrofluoric acid. After sonication and chromatography in the ultra-gravity field for the etched products, aqueous solution with QDs can be obtained. The microstructure evolution of raw particles and optical properties of QDs were measured. Different organophilic groups on the surface like carboxyl, oxygroup, and hyfroxy were produced in the process of etching. Fluorescent labeling and imaging for living cells of Aureobasidium pulluans were investigated. The results indicated that SiC QDs were not cytotoxic and could stably label due to the conjugation between organophilic groups of QDs and specific protein of cells, it can be utilized for fluorescent imaging and tracking cells with in vivo and long-term-distance. Moreover, mechanism and specificity of mark were also analyzed.
文摘Nowadays the development of Internet of Things （loT） and defense technologies imperatively needs high-performance photodetectors that can work in a broadband wavelength range, in particular, covering the mid-infrared （MIR） region [1]. This generates great interest in the incorporation of a series of novel optoelectronic materials and structures into the photodetectors. Graphene and colloidal quantum dots （QDs） are key players among novel materials used to fabricate high-performance photodetectors [2-4]. By taking advantage of the high mobility of graphene and excellent tunable optical absorption of colloidal QDs,
基金supported by the National Natural Science Foundation of China(Nos.61575168 and 61265009)the Xinjiang Science and Technology Project(No.201412112)
文摘The fluorescence of graphene oxide quantum dots （GOQDs） that are infiltrated into porous silicon （PSi） is investigated. By dropping activated GOQDs solution onto silanized PSi samples, GOQDs are successfully in- filtrated into a PSi device. The results indicate that the intensity of the fluorescence of the GOQD-inflltrated multilayer with a high reflection band located at its fluorescence spectra scope is approximately double that of the single layer sample. This indicates that the multilayer GOQD-infiltrated PSi substrate is a suitable material for the preparation of sensitive photoluminescence biosensors.
文摘采用射频和脉冲磁控共溅射法并结合快速光热退火法制备了含硅量子点的SiC_x薄膜.采用掠入射X射线衍射、喇曼光谱、紫外-可见-近红外分光光度计和透射电子显微镜对薄膜进行表征.研究了脉冲溅射功率对薄膜中硅量子点数量、尺寸、晶化率和薄膜光学带隙的影响.结果表明:当溅射功率从70 W增至100 W时,硅量子点数量增多,尺寸增至5.33nm,晶化率增至68.67%,而光学带隙则减至1.62eV;随着溅射功率进一步增至110 W时,硅量子点数量减少,尺寸减至5.12nm,晶化率降至55.13%,而光学带隙却增至2.23eV.在本实验条件下,最佳溅射功率为100 W.
文摘采用脉冲激光烧蚀法,以多晶3C-SiC陶瓷片为靶材,制备了悬浮于去离子水中的非晶SiC纳米颗粒。利用透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、傅里叶变换红外吸收光谱(FTIR)、紫外可见吸收光谱(UV-Vis)和光致发光谱(PL)等测试手段对其形貌、结构和光学性质进行了分析。结果表明:这些纳米颗粒由大量的非晶SiC构成,粒径在8~9 nm,光学带隙为3.28 e V;样品表现出较强的光致发光,发光峰位于415 nm处,这主要是由于量子限制效应造成的。
基金Acknowledgements This work was supported by Key Project of Chinese National Programs for Fundamental Research and Development（Grant No. 2010CB631002）, National Natural Science Foundation of China （Grant No. 50771078, 50901057） and Xi＇ an Applied Materials Innovation Fund （XA-AM- 200904） . The authors thank Guo S W and Li Y H for their help with the HRTEM operation.
文摘采用磁控共溅射沉积法,以Si靶和SiC靶为靶材,单晶Si(100)和石英为衬底,在不同衬底温度下沉积了富硅SiC_x薄膜。在氮气氛下于1100℃退火,得到包含硅量子点的SiC_x薄膜。采用傅立叶变换红外吸收光谱、拉曼光谱、掠入射X射线衍射和吸收谱对退火后的SiC_x薄膜进行了表征。结果表明:当衬底温度从室温(25℃)升至300℃时,薄膜的晶化率增至71.3%,硅量子点尺寸增至8.9 nm,而光学带隙则减至2.42 e ;随着衬底温度进一步升高,薄膜的晶化率降至63.1%,硅量子点尺寸减小至7.3 nm,而光学带隙却增加至2.57 e ;当衬底温度从室温(25℃)升至400℃时,薄膜的吸收系数呈先增大后减小趋势。在本实验条件下,最佳衬底温度为300℃。
基金partially supported by the National Natural Science Foundation of China(Grant Nos.51402161,51373086,21606140,and 21776147)the Natural Science Foundation of Shandong Province(Grant No.ZR2021YQ32)the Taishan Scholar Project of Shandong Province(tsqn201909117).
文摘The combination of SiC quantum dots sensitized inverse opal TiO_(2) photocatalyst is designed in this work and then applied in wastewater purification under simulated sunlight.From various spectroscopic techniques,it is found that electrons transfer directionally from SiC quantum dots to inverse opal TiO_(2),and the energy difference between their conduction/valence bands can reduce the recombination rate of photogenerated carriers and provide a pathway with low interfacial resistance for charge transfer inside the composite.As a result,a typical type-II mechanism is proved to dominate the photoinduced charge transfer process.Meanwhile,the composite achieves excellent photocatalytic performances(the highest apparent kinetic constant of 0.037 min^(-1)),which is 6.2 times(0.006 min^(-1))and 2.1 times(0.018 min^(-1))of the bare inverse opal TiO_(2) and commercial P25 photocatalysts.Therefore,the stability and non-toxicity of SiC quantum dots sensitized inverse opal TiO_(2) composite enables it with great potential in practical photocatalytic applications.
基金the Defense Advanced Research Projects Agency of the United States under Grant No.W911NF-04-1-0429
文摘Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent progress of the direct epitaxy and fabrication of quantum dot （QD） lasers and integrated guided-wave devices on silicon. This approach involves the development of molecular beam epitaxial growth of self- organized QD lasers directly on silicon substrates and their monolithic integration with amorphous silicon waveguides and quantum well electroabsorption modulators. Additionally, we report a preliminary study of long-wavelength （〉 1.3 μm） QD lasers grown on silicon and integrated crystalline silicon waveguides using membrane transfer technology.
