尼古拉·卡卢金博士

We have revealed a previously unobserved type of electronic state with a relatively strong optical response tied to the interface junction between graphene sheets with different number of monolayers on each side of the junction. 这些界面状态 are localized and have an enhanced dipole matrix element for interband excitation. Photo-excited electrons generate photocurrent and photovoltage at the rectifying junction between suspended and nonsuspended parts of graphene flakes. 因为是一维的 geometry, the interface junction states support a polarization dependent photocurrent which is aligned along the junction in inhomogeneous graphene samples.

Altogether, our results demonstrate the capability of graphene interface junctions to form 1D electronic states, whose properties can be exploited for electronic and 光电应用程序. We discovered these 石墨烯的状态 but we anticipate that similar type of states will be important and will definitely influence physical properties for all other 2D few-monolayer semiconducting materials.

最近的出版物

尼古拉G. 卡卢金，雷静，Eric Suarez Morell, Gregory C. Dyer, 李Wickey, Mekan Ovezmyradov, Albert D. 格林，迈克尔·C. 万科,埃里克. A. 刘春宁，刘易. F. 托雷斯、失落 米哈伊尔·V. 弗斯特尔和康斯坦丁. Efetov, Photoelectric polarization-sensitive broadband photoresponse from interface junction 石墨烯的状态[j]，二维材料，4 (2017):015002.

最近的演讲

尼古拉G.卡卢金，雷静，Eric Suarez Morell, Gregory C. Dyer, 李Wickey, Mekan Ovezmyradov, Albert D. 格林，迈克尔·C. 万科,埃里克. A. 刘春宁，刘易. F. 托雷斯、失落 米哈伊尔·V. 拳头，和康斯坦丁B. Efetov, Interface junction states and broadband polarization-sensitive inhomogeneous graphene. 石墨烯 2017, Barcelona, Spain, March 28-31, 2017.

We have developed a method to synthesize small ∼ 3– 18nm尺寸的Er₂O₃– Er₂SO₂  nanocrystals dispersed on rGO  (reduced 石墨烯 Oxide) surfaces. 高度的 表面覆盖率₂O₃– Er₂SO₂ nanoparticles on the surface of rGO was achieved. 这个结果很可能是硫磺造成的 impurities in the GO starting material which act as nucleation sites for the formation 的呃₂O₃– Er₂SO₂  热还原过程中的颗粒. Despite the small size, due to high concentration 的呃³⁺ , the nanocrystals demonstrate strong PL and upconversion response. 因此， this work provides a promising solution towards making Er³⁺ - based imaging probes and upconversion sensors for biomedical applications.

最近的出版物

N. G. 卡卢金, A. J. 罗伊,K. Artyushkova,. Serov, Synthesis, characterization, and photoluminescence 的呃₂O₃–Er₂SO₂ 还原氧化石墨烯上的纳米颗粒, 纳米技术 28 (2017), 195603.

研究ers at the University of New Mexico and 威尼斯人app下载 have recently developed a method of making graphene-based inorganic-organic hybrid materials for application in fine organic synthesis and separation of enantiomers. 这些合成的杂化物 materials can be created in multi-step reactions which involve preparation of graphene-based materials, with controlled morphology and chemical composition, followed by modification of graphene-based materials by organic molecules. 这些目标应用程序 materials are in pharmacy, fine organic synthesis, and separation of chiral compounds.

最近申请的专利

P.Atanassov,.Serov,  N. 卡卢金, L.Frolova,  石墨烯-Based Inorganic-Organic Hybrid Materials and Separation of Racemic Mixtures, WO2016054129 A1.

的 problem of accurate measurements of flowrate and compositions of oil–gas–water mixtures in a pipeline remains one of the key challenges of petroleum industry. 的 currently used methods are expensive, slow, not portable, and in some cases require extra safety measures (for example, gamma radiation-based flowmeters). 在我们的工作中， we provide the solution of the three-phase flow problem based on use of Mid and Far-Infrared 激光光谱学. We describe the technique and the device, which provides real time composition analysis not only for the three major components of flow (oil, water, and gas), but also can monitor the changes in composition of oil, gas, and water components at the level of a chemical analytical laboratory. 演示的技术不是 only much more informative, but less expensive, safer, less energy consuming, and much more compact as compared existing alternatives.

最近的出版物

T. Ispirescu R.巴尔奇, N.G.卡卢金. In-situ analysis of mixed-phase oil flow compositions via Mid and Far- Infrared laser 光谱学, Submitted 02/10/2018, SPE Journal, manuscript SJ-0218-0016

最近的专利

R. 鲍尔奇T. Ispirescu, N.卡卢金, Method of in-situ analysis of mixed phase flow composition， NMT专利申请WSGR摘要号. 47481-703.101, 04/ 2016.

研究 of 2D semiconductors is one of the most rapidly progressing areas of solid 物理状态. Two-dimensional GaSe provides advantages not present in bulk GaSe: the bandgap has been predicted to enlarge up to 4 eV, and atomically thin layers provide a pathway towards novel responses emerging from 2D heterostructures. 最近,超薄 GaSe photodetectors have been successfully fabricated demonstrating comparably large 光响应和快速响应时间.A limitation of ultrathin GaSe is its sensitivity 氧化. Our work demonstrates both the proclivity of ultrathin GaSe to oxidize and the Raman-based spectral signatures that can be utilized to track its occurrence. Specifically, the products of the oxidation reaction, namely, those stemming from Ga₂Se₃ and a-Se, are shown to evolve in conjunction with the reduction of photoluminescence and Raman scattering intensity associated with GaSe. 而暴露后会发生氧化 to ambient air, it can be accelerated via photoinducement, thereby presenting the possibility of patterned 2D heterostructures realized by laser processing that transforms 固体本身.

最近的出版物

T.E. Beechem B.M. 科瓦尔斯基,M.T. Brumbach,.E. 麦当劳,C.D. Spataru,年代.W. 豪厄尔, T. 太,我.A. 帕斯克和 N.G. 卡卢金, 超薄GaSe的氧化, :. 理论物理. 列托语. 107 , 173103 (2015).

最近的演讲

T. E. Beechem B. M. 科瓦尔斯基,M. T. Brumbach,. E. 麦当劳,C. D. Spataru,年代. W. 豪厄尔,T. 太,我. A. 帕斯克和 N. G. 卡卢金, 超薄GaSe的氧化, 2016 MRS Spring Meeting and Exhibit, Presentation NT 4.8.3月28日至4月1日 2016年，亚利桑那州凤凰城

兴趣范围:

• 奈米制造
• CVD和石墨烯的机械剥离
• 石墨烯的拉曼表征
• magnetotransport实验

兴趣范围:

• 光和磁输运实验
• 太赫兹激光
• 微波和太赫兹光谱学
• 数据采集系统 

• 克里斯托弗·德尔·巴尔加
• Irakli Kalichava(硕士，现为博士.D 学生, Paul Scherrer Institute, Villigen, 瑞士)
• Dr. 格雷厄姆·沃尔什
• 阿曼达·克莱门茨
• 拉塞尔•菲利普斯