Achintya Singha

Achintya Singha
Associate Professor

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Previous appointments:

National Enterprise for nanoScience and nanoTechnology(NEST), Scuola Normale Superiore (SNS),  Pisa, Italy (Mar, 2007-Jan, 2010)

Research interests:

      Raman Spectroscopy at high pressure and low temperature

      Nanomaterials 

      2D materials (Graphene, TMDCs, etc.) 

      Electron correlation effects in semiconductor quantum structures

      Surface Enhanced Raman Scattering (SERS)



Contact:

Address: Department of Physics
Main Campus
Bose Institute
93/1, A. P. C. Road
Kolkata - 700 009, India
E-Mail: achintya[at]jcbose.ac.in
Phone: +91-33-23031177

Research:

Vibrational and electronic properties of one-dimensional systems under high pressure and photo-irradiation:

Semiconductor nanowires (NWs) have been intensively studied in recent years due to their potential applications in the new generation of extraordinary tiny devices.  For these applications, a deeper understanding of the fundamental properties of the NWs, under different thermodynamic parameters, is required. Here, we study  the prominent role of pressure in modifying the vibrational and electronic properties of one-dimensional systems and demonstrate the Raman spectroscopy as a non-contact tool to study the photothermal effects in nanoscale materials and shows how optical control over hole density can be achieved in InAs NWs.







Study of 
thermophysical properties of nanoscale materials using Raman spectroscopy



Defect-engineered nanostructures are gaining interest in the past few years due to their interesting mechanical, thermo-electrical and electronic properties. We report a noninvasive optical technique based on micro-Raman spectroscopy to study the  thermo- physical properties of normal (non-defective) and twinned (defective) Ge NWs based on Raman spectroscopy. The role of lamellar twinning and polytype phase on the heat transport properties of NWs has been demonstrated. 



Non-equilibrium Induction of Tin in Germanium: Direct Bandgap Ge1-xSnx Nanowires

A non-equilibrium group IV nanoscale alloy has been developed to achieve new functionalities, such as the formation a direct bandgap in semiconductors where indirect bandgap elemental semiconductors are conventional. Here, we report the application of a three-phase bottom-up growth protocol to fabricate highly crystalline, uniform diameter, direct bandgap Ge1-xSnx nanowires with considerable Sn incorporation. A direct bandgap has been identified for the first time for Ge1-xSnx nanowires. This work addresses towards the ongoing demand for a nanoscale material for group IV photonics.  



Tuning optical property of few-layer LTMDs by decoration with noble metal nanoparticles

In mono/few-layer Layered transition metal dichalcogenides (LTMDs), due to the presence of strong Coulomb interactions, optically generated electron–hole pair forms stable exciton states even at room temperature. So, the carrier density plays a significant role in determining the optical properties of mono/few-layer TMDs.  Doping is one of the effective techniques to control the carrier density in a material. Here, we have shown an easy and inexpensive chemical route for the doping of few-layer MoS2 with Au nanoparticles (NPs). The Au-NPs are formed on the defective sites of the MoS2 and localized by a non-covalent bond. An enhancement in the photoluminescence (PL) intensity of the Au-MoS2 composite with respect to bare few-layer MoS2 has been observed. We also systematically observed a blueshift in the excitonic emission as the number and size of the Au-NPs on MoS2 increases. Both phenomena have been understood to result from the switching between charged exciton (trion) recombination and neutral exciton recombination.





Surface-Enhanced Raman Scattering (SERS)


SERS combines molecular fingerprint specificity with single-molecule detection, which is the ultimatesensitivity required in chemical analysis, trace detection and bio-sensing. Defined and reproducible assembly of nanoparticle clusters plays an important role in the development of SERS substrates.  Here, we have used a simple and inexpensive method to fabricate self-assembled wirelike Ag nano clusters (Ag-NCs) in a DNA template. We addresses different fundamental aspects of SERS, such as the dependence of the enhancement on the orientation of nanostructures with respect to the polarization of the incident light and the stability of the signals. We believe that the DNA-based synthesis technique might be useful for the formation of a series of new nanogap structures for other materials with uniform morphology that might act as a potential SERS substrate for label-free biomedical sensing, Raman imaging, and NPs-based photothermal therapeutics.

Publications:

  1. Maiti R. , Haldar S., Majumdar D.,  Singha A. and Ray S. K. Hybrid opto-chemical doping in Ag nanoparticle-decorated monolayer graphene grown by chemical vapor deposition probed by Raman spectroscopy. Nanotechnology 28 (2017) 075707 (8pp)
  2. Samanta S., Saini D., Singha A., Das K., Bandaru P.R. and  Rao A. M. and Raychaudhuri A. K. Photoresponse of a Single Y-Junction Carbon Nanotube. ACS Applied Materials & Interfaces (2016)  8 (29), 19024-19030.
  3. Majumdar D., Ercolani D., Sorba L. and  Singha A. Laser induced photothermal effects on InAs nanowires: tuning the hole density. Journal of Materials Chemistry C (2016) 4 (12), 2339-2344.
  4. Biswas S., Doherty J., Saladukha D., Ramasse Q., Majumdar D., Upmanyu M., Singha A., Ochalski T., Morris M. A. and Holmes J. D. Non-equilibrium induction of tin in germanium: towards direct bandgap Ge1-xSnx nanowires. Nature Communications (2016) 11405 (7), 1-12.
  5. Konar A., Sarkar T., Chakraborty I., Sukul N.C., Majumdar D., Singha A. and Sukul A. Raman spectroscopy reveals variation in free OH groups and hydrogen bond strength in ultrahigh dilutions. International Journal of High Dilution Research (2016) 15 (2),2-9.
  6. Ansari Z., Sarkar K., Saha A., Singha A. and Sen K. Enhanced anion sensing by γ-irradiated polyphenol capped iron oxide nanoparticles. Journal of Radioanalytical and Nuclear Chemistry (2016) 308 (2), 517-525.
  7. Ghatak S.K., Sen S., Majumdar D., Singha A. and Sen K.  Peanut proteins in periodate specific anion sensing: An ensuing reduction in allergic response.  Food chemistry (2016) 197, 1286-1291.
  8. Sarkar T., Konar A., Sukul N.C., Majumdar D., Singha A. and Sukul A.  Raman spectroscopy shows difference in drugs at ultra high dilution prepared with stepwise mechanical agitation.  International Journal of High Dilution Research (2016) 15 (1), 2-9.
  9. Majumdar D., Biswas S., Ghoshal T. and  Holmes J.D. and Singha A. Probing Thermal Flux in Twinned Ge Nanowires through Raman Spectroscopy. ACS applied materials & interfaces (2015) 7 (44), 24679-24685.
  10. Ghatak S.K., Majumdar D., Singha A,. Sen S., Das D., Chakrabarti A., Mukhopadhyay C. and Sen K. Peanut protein sensitivity towards trace iron: a novel mode to ebb allergic response. Food chemistry (2015) 176, 308-313.
  11. Biswas S., Doherty J., Majumdar D., Ghoshal T., Rahme K., Conroy M.,   Singha A.,  Morris M. and Holmes J. D. Diameter-Controlled Germanium Nanowires with Lamellar Twinning and Polytypes. Chemistry of Materials (2015) 27 (9), 3408-3416.
  12. Singha S. S., Nandi D. and Singha A. Tuning the photoluminescence and ultrasensitive trace detection properties of few-layer MoS2 by decoration with gold nanoparticles, RSC Advances (2015)  5 (31), 24188–24193.
  13. Chowdhury A, Iyyappan R, Majumdar D and  Singha A. Structural and spectroscopic characterisations of the surface oxide scales and inclusions present on edge-burst hot-rolled steel coils.  Materials Chemistry and Physics (2014) 148 (1), 276-283.
  14. Majumdar D,  Basu  A, Mukherjee G D,  Ercolani D, Sorba  L,  Singha A. Raman scattering study of InAs nanowire under high pressure. Nanotechnology, (2014) 25 (46)  465704.
  15. Giri A, Goswami N, Sasmal C, Polley N, Majumdar D, Sarkar S, Bandyopadhyay S N, Singha A and Pal S K Unprecedented catalytic activity of Mn3O4 nanoparticles: potential lead of a sustainable therapeutic agent for hyperbilirubinemia. RSC Advances (2014)4, 5075-5079.
  16. 16. Mitra S, Singha A and Chakravorty D. Non-linear temperature variation of resistivity in graphene/silicate glass nanocomposite. Journal of Physics D: Applied Physics (2013) 46 (37), 375306. 
  17. Giri A, Goswami N, Sasmal C, Polley N, Majumdar D, Sarkar S, Bandyopadhyay S N, Singha A and Pal S K Unprecedented catalytic activity of Mn3O4 nanoparticles: potential lead of a sustainable therapeutic agent for hyperbilirubinemia. RSC Advances (2014)4, 5075-5079.
  18. Majumdar D, Singha A, Mondal P  K and Kundu S DNA-Mediated Wirelike Clusters of Silver Nanoparticles: An Ultrasensitive SERS Substrate. ACS Applied Materials and Interfaces (2013) 5 (16), 7798−7807.
  19. Panda J K, Roy A, Singha A, Gemmi M, Ercolani D, Pellegrini V and Sorba L Internal field induced enhancement and effect of resonance in Raman scattering of InAs nanowires. Solid State Communications (2013) 160, 26-31.
  20. Rakshit S, Saha R, Singha A, Seddigi Z S A, Pal S K  Molecular interaction, co-solubilization of organic pollutants and ecotoxicity of a potential carcinogenic fuel additive MTBE in water. Journal of Molecular Liquids (2013)180,  235-243. 
  21. Saha R, Rakshit S, Majumdar D, Singha A, Mitra R K and Pal SK. Nanostructure, solvation dynamics, and nanotemplating of plasmonically active SERS substrate in reverse vesicles. Journal of Nanoparticle Research (2013) 15 (4) 1576 (1-12).  
  22. Giri A., Goswami N., Pal M., Zar Myint M. T., Al-Harthi S., Singha A., Ghosh B., Dutta J., Pal S.K. Rational surface modification of Mn3O4 nanoparticles to induce multiple photoluminescence and room temperature ferromagnetism. Journal of Materials Chemistry C (2013) 1 (9),  1885-1895.     
  23. Sarkar S., Makhal A., Bora T., Lakhsman K., Singha A., Dutta J., Pal S.K. Hematoporphyrin-ZnO nanohybrids: Twin applications in efficient visible-light photocatalysis and dye-sensitized solar cells,  ACS Applied Materials and Interfaces (2012) 4 (12), 7027-7035.
  24. Biswas S., Singha A., Morris M. A., and Holmes J. D. Inherent Control of Growth, Morphology, and Defect Formation in Germanium Nanowires. NanoLetters, (2012) 12 (11), 5654−5663.
  25. Panda J. K., Roy A., Singha A., Gemmi M., Ercolani D., Pellegrini V., and Sorba L. Raman sensitivity to crystal structure in InAs nanowires. Applied Physics Letters, (2012) 100, 143101 1-3.
  26. Gamucci A., Pellegrini V.,  Singha A.,  Pinczuk A.,  Pfeiffer L. N.,  West K. W. and Rontani M. Probing the spin states of three interacting electrons in quantum dots. Physical Review B, (2012) 85 (3), 033307 (1-4).
  27. Singha A., Gibertini M., Karmakar B., Yuan S., Polini M., Vignale G., Katsnelson M. I., Pinczuk A., Pfeiffer L. N., West K.W., and Pellegrini V. Two-dimensional Mott-Hubbard electrons in an artificial honeycomb lattice. Science (2011)  332(6034), 1176.
  28. De Simoni, G., Singha A., Gibertini M., Karmakar B., Polini M., Piazza V., Pfeiffer L.N., West K.W., Beltram F. and Pellegrini V. Delocalized-localized transition in a semiconductor two-dimensional honeycomb lattice, Applied Physics Letters, (2010) 97 (13), 132113-3.  
  29. Singha A., Pellegrini V., Pinczuk A., Pfeiffer L.N., West K.W. and Rontani M. Correlated electrons in optically tunable quantum dots: Building an electron dimer molecule, Physical Review Letters, (2010) 104 (24), 246802-4.
  30. Gibertini M., Singha A., Pellegrini V., Polini M., Vignale G., Pinczuk A., Pfeiffer L.N. and  West K.W.  Engineering artificial graphene in a two-dimensional electron gas. Physical Review, B (2009) 79 (24), 241406 (R)-4.
  31. Singha A., Pellegrini V., Kalliakos S., Karmakar B., Pinczuk A., Pfeiffer, L. N. and West K.W. Optical anisotropy of electronic excitations in elliptical quantum dots. Applied Physics Letters, (2009) 94 (7), 073114-3.                 
  32. Kalliakos S., Rontani M., Pellegrini V., Pinczuk A., Singha A., Garcia C. P., Goldoni G., Molinari E., Pfeiffer L.N. and West K.W. Probing collective modes of correlated states of few electrons in semiconductor quantum dots. Solid State Communications, (2009)  149, 1436-1442.
  33. Singha A., Roy A., Sonkusare A., Kumar P. and  Kaul A.D. Measuring nanoNewton forces with an indigenous atomic force microscope. Current Science, (2007) 93 (8), 1063-1070. 
  34. Mal S., Singha A., Dhara S. and  Roy A. Raman measurements and stress analysis in gallium ion-implanted gallium nitride epitaxial layers on sapphire. Thin Solid Films (2006) 515(4), 2798-2802. 
  35. Ojha A. K., Singha A., Dasgupta S., Singh R.K. and Roy A. pH dependent surface enhanced Raman study of Phe + Ag complex and DFT calculations for spectral analysis. Chemical Physics Letters, (2006) 431(1), 121-126.
  36. Singha A., Roy A., Kabiraj D. and  Kanjilal D. A hybrid model for the origin of photoluminescence from Ge nanocrystals in a SiO2 matrix,  Semiconductor Science and Technology, (2006) 21(12), 1691-1698.
  37. Singha A., Ghosh A., Roy A. and  Ray N.R. Quantitative analysis of hydrogenated diamondlike carbon films by visible Raman spectroscopy, Journal of Applied Physics(2006) 100 (4), 044910-8. 
  38. Singha A. and Roy A. Quantitative analysis of thermal stability of CdSe/CdS core-shell nanocrystals under infrared radiation. Journal of Materials Research, (2006) 21 (6), 1385-1389.
  39. Singha A., Dasgupta S.  And  Roy A. Comparison of metal-amino acid interaction in Phe-Ag and Tyr-Ag complexes by spectroscopic measurements. Biophysical Chemistry, (2006) 120 (3), 215-224.
  40. Singha A. and Roy A. Phonon confinement and surface phonon modes in CdSe-CdS core-shell nanocrystals. Reviews on Advanced Materials Science, (2005)10, 462-466.
  41. Singha A., Satpati B., Satyam P. V. and  Roy A. Electron and phonon confinement and surface phonon modes in CdSe-CdS core-shell nanocrystals. Journal of Physics Condensed Matter (2005) 17 (37), 5697-5708. 
  42. Ray S., Pramanik P., Singha A.  and  Roy A. Optical properties of nanocrystalline Y2O3:Eu3+,  Journal of Applied Physics (2005) 97 (9), 094312-6.
  43. Singha A., Dhar P.  and  Roy A. A nondestructive tool for nanomaterials: Raman and photoluminescence spectroscopy. American Journal of Physics (2005) 73 (3), 224-233. 

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Recognition:

  • Best Ph. D. Thesis Award in 51st DAE Solid State Physics Symposium (2006) held at Barkatulla University, Bhopal, India,

Teaching:

v  Int. M.Sc-Ph.D Physics course of Bose Institute and Univ. of Calcutta (2014 - present): Fall Semester

Ø Solid State Physics I (Paper code: CT-SSP-I)

 

v  Ph. D. coursework of Bose Institute (2014 - present):

Ø  Introduction to some advanced techniques in Biology (B5) (Coordinator)  

Ø  Microscopy and Micro-Raman spectroscopy (B23)

 

v  M. Sc. Physics Courses of St. Xavier's College and Bose Institute (2013): Autumn semester

Ø  Electrodynamics 1 (Paper Code: MPHC4205)

Present:

Image Name Designation Department Campus Contact number Email
profile image Sreyan Raha JRF Physics Main 23031194 sreyan
profile image Tara Shankar Bhattacharya SRF(I) Physics Main 23031194 tarashankar1992@mail.jcbose.ac.in

Former:




Dr.
Achintya Singha

Associate Professor

Department of Physics,

Bose Institute

E-mail: achintya@jcbose.ac.in

Present Research Scholars





Shib Shankar Singha



SRF



M.Sc. IIT Delhi



shibshankarsingha178@gmail.com



2013-till date




Tara Shankar Bhattacharya



JRF



M.Sc.-Bose Institute



tarashankar1992@gmail.com



2015-till date




Sreyan Raha



JRF



M.Sc.-Bose Instute



sreyanraha@gmail.com



2016-till date


Past Members







Dr. Dipanwita
Majumdar (2010-2016)

Thesis Title:
Study of Nanomaterials and Ultra Sensitive Molecular Detection using Raman Spectroscopy

Current Position:

DST-INSPIRE Faculty, Department of Physics, IISc. Bangalore (from April 2017).

Present Project Students

Sudip BhowmickM.Sc.4th Semester Project, Integrated M.Sc.-Ph.D. Student 2015-172017
Payashwini MaitraSummer Project & M.Sc. Project, Adamas University, 2015-172016-17

Past Project Students:

NameProject & AffiliationCurrent AffiliationYear
Sucheta Sharma
M.Sc. Project, St. Xaviers College
Marie Curie Early Stage Researcher, Ametek Buisness unit Luphos, Germany
2013
Dipanjan Nandi
Summer Project, M.S., IIT Kharagpur
Research Scholar, University of Alberta
2014-15
Tara Shankar Bhattacharya
M.Sc. Project Student, Bose Institute
Junior Research Fellow, Bose Institute
2015
Paritosh Piyush Sahu
B.Tech., NIST, Berhampore
NIST, Berhampore, Odisha
2015
Sreyan Raha
M.Sc. Project Student, Bose Institute
Junior Research Fellow, Bose Institute
2016
Ananya BiswasWinter Project, BS-MS, IISER KolkataBS-MS, IISER Kolkata
2016

Group News:

1. February, 2017 -  Dr. Dipanwita Majumdar was awarded INSPIRE faculty fellowship.
2. August, 2016- Dipanwita Majumdar(SRF)  awarded Ph.D. degree.
3. March, 2017- Shib Shankar Singha(SRF) awarded best poster award at the"One day Symposium on Nanotechnology: From Materials to Medicines and their Social Impact" held at BITM Kolkata during March 25, 2017
4. December, 2015- Tara Shankar Bhattacharya(JRF) awarded second best poster award at the "International Conference on Frontiers in Material     Science and Technology" organized by National Institute of Science & Techlogy during December 10-12, 2015