Prof.K.S.Sangunni

   Department of Physics

   Indian Institute of Science

    Bangalore,India.

   e-mail: sangu@physics.iisc.ernet.in

   Tel: 91 - 80 - 22933279

   Fax: 91 - 80 - 2360 2602


Research Interest

Selected Papers

Publications after 1994

Conferences

Group




Research Interest

Role of defects in chalcogenide glasses.

p to n conduction changes in glasses.

Light induced anisotropies in glasses.

Optical properties of amorphous thin films.




Selected Papers

Determination of thermal diffusion length in bismuth doped chalcogenide glasses by Photoacoustic technique
B.Thangaraju, R.Ganesan, N.Asha Bhat, K.S.Sangunni, E.S.R.Gopal
Jl of Optoelectronics and Advanced Materials 2 (2000) 91
A Consistent Approach towards the Bi doping Mechanism in Ge-Se based Chalcogenide Glasses with Cp Measurement in Ge-Se-Te-Bi system
N.Asha Bhat and K.S.Sangunni
Solid State communication 116 (2000) 297
Programmable control of Temperature: A simple and versatile method
N.Asha Bhat and K.S.Sangunni
Jl. Instrum.Soc.India 30(1) (2000) 29.
The role of defects in carrier type reversal in Bismuth doped Ge-Se glases by photoluminescence spectroscopy
N.Asha Bhat,K.S.Sangunni and K.S.R.K.Rao
Jl of Optoelectronics and Advanced Materials 3 (2001) 735
A Fourier-transform photoluminescence study of radiative recombination mechanism in chalcogenide glasses
N.Asha Bhat,K.S.Sangunniand K.S.R.K.Rao
Journal of Non-Crystalline Solids 319 (2003) 192-199
Mixed doping in Ge(10) Se(90-x-y)In(x)Bi(y) glasses
N.Asha Bhat,K.S.Sangunniand A.Kumar
Journal of Non-Crystalline Solids 44(4) (2003) 296-302
Enhancement of Photoluminescence intensity by photoinduced interdiffusion in nanolayered a-Se/As(2)S(3) films
K.V.Adarsh, K.S.Sangunni S.Kokenyesi, I.Ivan and M.Shipljak
Journal of Applied Physics 97, 0443314 (2005)





Publications after 1994

Experimental determination of melt-solid interface shapes and actual growth rates of Gallium Antimonide grown by vertical Bridgman method
P.S.Dutta, K.S.Sangunni, H.L.Bhat and Vikram Kumar
J.Crystal Growth 141 (1994) 476

Growth of gallium antimonide by vertical Bridgman technique with planar crystal-melt interface
K.S.Sangunni, H.L.Bhat and Vikram Kumar
s J.Crystal Growth 141 (1994) 44

Donor-related deep level in bulk GaSb
P.S.Dutta, K.S.R.Koteswara Rao, K.S.Sangunni and H.L.Bhat
Appl.Phys.Lett 65 (11)(1994) 1412

Sulphur passivation of gallium antimonide surfaces
P.S.Dutta, K.S.Sangunni, H.L.Bhat and Vikram Kumar
Appi.Phys.Lett 65(13) (1994) 1695

Polarization Fluctuations in G-irradiated Triclycine Sulphate
R.Ravi, K.S.Sangunni and P.S.Narayanan
Ferroelectrics 155 (1994) 97

Non-isothermal transformation of Pb-modified Ge-Se glasses
M.K. Rabinal, N. Ramesh Rao, K.S. Sangunni and E.S.R. Gopal
Phil. Mag. B 70 (1994) 89 - 99.

Heat capacity measurement on Ge20Se80-xBix glasses
M.K. Rabinal, K.S. Sangunni, E.S.R. Gopal and S.V. Subramanyam,
Solid State Commun. 88 (1994) 251 - 254.

Neutron diffraction study of GexSe1-x glasses
N.Ramesh Rao, K.S. Sangunni, E.S.R. Gopal, P.S.R. Krishna, R. Chakravarthy and B.A. Dasannacharya,
Physica B 213&214 (1995) 561 - 563.

Specific heat measurements on Ge-Se-In glasses
M.K. Rabinal, K.S. Sangunni, S.V. Subramanyam and E.S.R. Gopal
Phys. Chem.Glasses 36 (1995) 50-52.

Minimum fragility in GexSe80-xPb20 glasses
M.K. Rabinal, K.S.Sangunni, E.S.R. Gopal and S.V.Subramanayam,
Physica B 205 (1995) 403-407.

Chemical ordering in Ge20Se80-xInx glasses
M.K. Rabinal, K.S.Sangunni and E.S.R. Gopal
J. Non-Cryst. Solids 188 (1995) 98-106.

Composition Dependence of the Glass Transition in Ge-Se-Te Glasses
R.Ganesan, K.N.Madhusoodanan, K.S.Sangunni and E.S.R.Gopal
Phys.Stat.Sol 190 (1995) k23

Electrical characterization of surface defects in GaSb created by hydrogen plasma
P.S.Dutta, K.S.Sangunni and H.L.Bhat
Appl.Phys.Lett 66 (1995) 1966

Optical and electrical properties of hydrogen-passivated gallium antimonide
P.S.Dutta, K.S.Sangunni and H.L.Bhat
Physical Review B 51 (1995) 2153

Devitrified phases in CuAsSe glasses
N.Ramesh Rao M.K. Rabinal, K.S.Sangunni and E.S.R. Gopal,
Physica B 225 (1996) 274 - 282.

Crystallisation studies on CuxGe15Te85-x glasses
K.Ramesh, S.Asokan, K.S.Sangunni and E.S.R Gopal
J Phys: Condens. Matter 8 (1996) 2755-2762.

Compositional dependence of high pressure resistivity behaviour of Cu-Ge-Te glasses
K.Ramesh, S.Asokan, K.S.Sangunni and E.S.R.Gopal,
Phys. Chem. Glasses 37 (1996) 217-220.

Structural correlation in GexSe1-x glasses-Neutron diffraction study
N.Ramesh Rao, P.S.R.Krishna, S.Basu, B.A.Dasannacharya, K.S.Sangunni and E.S.R. Gopal.
Journal Non Crystalline Solids 240 (1998) 221

Photoacoustic measurement of the thermal diffusivity of Bi Added Ge-Se and Ge-Se-Te Glases
B.Thangaraju, R.Ganesan, K.S.Sangunni and E.S.R Gopal
Solid State Communications Vol 109 (5) 301 1998

Effect of topological thresholds on thermal behaviour of germanium telluride glasses containing metallic additives
K.Ramesh, S Asokan K.S.Sangunni and E.S.R. Gopal
The European Physical Journal B 6, 207 .1998

Electrical resistivity behaviour of Ag-Ge-Te glasses under pressure at different temperatures: the influence of bonding and topological thresholds
K.Ramesh, S Asokan K.S.Sangunni and E.S.R. Gopal
J.Phys:Condens.Matter 11(1999) 3897

Optical and Thermal diffusivity Measurement of Ge-Se-Te Glasses by Photoacoustic Technique
R.Ganesan, K.N.Madhusoodanan, A.Srinivasan,K.S.Sangunni and E.S.R.Gopal
Phys.Stat.Sol 212 (1999) 223

Electrical switching in germanium telluride glasses doped with Cu and Ag
K.Ramesh, S.Asokan, K.S.Sangunni and E.S.R.Gopal
Appl.Phys.A 69 (1999) 421-42522

Glass formation in germanium telluride glasses containing metallic additives
K.Ramesh, S.Asokan, K.S.Sangunni and E.S.R.Gopal
Jl of Phys and chem of solids 61 (2000) 95-101

Determination of thermal diffusion length in bismuth doped chalcogenide glasses by Photoacoustic technique
B.Thangaraju, R.Ganesan, N.Asha Bhat, K.S.Sangunni, E.S.R.Gopal ,
Jl of Optoelectronics and Advanced Materials 2 (2000) 91

A Consistent Approach towards the Bi doping Mechanism in Ge-Se based Chalcogenide Glasses with Cp Measurement in Ge-Se-Te-Bi system
N.Asha Bhat and K.S.Sangunni
Solid State communication 116 (2000) 297

Programmable control of Temperature: A simple and versatile method
N.Asha Bhat and K.S.Sangunni
Jl. Instrum.Soc.India 30(1) (2000) 29.

The role of defects in carrier type reversal in Bismuth doped Ge-Se glases by photoluminescence spectroscopy
N.AshaBhat, K.S.Sangunni and K.S.R.K.Rao
Jl of Optoelectronics and Advanced Materials 3 (2001) 735

Fourier-transform photoluminescence study of radiative recombination mechanism in chalcogenide glasses
N.Asha Bhat K.S.Sangunni and K.S.R.K.Rao
Journal of Non-Crystalline Solids 319 (2003) 192199

Mixed doping in Ge10Se90-x-yInxBiyglasses
N.Asha Bhat K.S.Sangunni and A.Kumar
Phys. Chem. Glasses, 2003, 44 (4), 296302

Enhancement of Photoluminescence intensity byphoto-induced inter-diffusion in nano layered a-Se/As2S3films
K.V.Adarsh, K.S.Sangunni, S.Kokenyesi, I.Ivan and M.Shipljak
Journal of Applied Physics, 97,044314 (2005).

Photoinduced interdiffusion in nanolayered Se/As2S3films: Optical and x-ray photoelectron spectroscopic studies
K.V.Adarsh, K.S.Sangunni , T.Shripathi, S.Kokenyesi and M.Shipljak
Journal of Applied Physics, 99,094301 (2006).

Luminescence in amorphous chalcogenide multilayers
K.V.Adarsh, K.S.Sangunni , S.Kokenyesi, I. Ivan and M. Shipljak
Phys.Chem.Glasses: Eur .J .Glass Sci. Technol. A,47 (2), 198 (2006).

Luminescence in amorphous chalcogenide multilayers
R. Naik, E. M. Vinod, C. Kumar, R. Ganesan, and K.S.Sangunni
Phys.Chem.Glasses: Eur .J .Glass Sci. Technol. A,47 (2), 198 (2006).

Kinetics and Chemical Analysis of Photo induced inter diffusion in nanolayered Se/As2S3 films.
K.V.Adarsh, Ramakanta Naik, K.S.Sangunni , S. Kokenyesi, H. Jain and A. C. Miller
Journal of Applied Physics 104, 053501 (2008)

X-ray Photoelectron Spectroscopic Studies on Se/As2S3 and Sb/As2S3 nanomultilayered film.
Ramakanta Naik, K.V.Adarsh, K.S.Sangunni , Uday despandey, T. Shripathi,V.Takats and S. Kokenyesi
Journal of Non-Crystalline Solids, 355, 1836 (2009)

In situ pump probe optical absorption studies on Sb/As 2S3 nanomultilayered film
Ramakanta Naik, R. Ganesan, K.V.Adarsh, K.S.Sangunni ,V.Takats and S. Kokenyesi
Journal of Non-Crystalline Solids,355, 1943 (2009)

Light and heat induced interdiffusion in Sb/ As2S3nano-multilayed film.
Ramakanta Naik, R. Ganesan, K.V.Adarsh, K.S.Sangunni ,V.Takats and S. Kokenyesi
Journal of Non-Crystalline Solids, 355, 1939(2009)

Compositional dependence on the optical properties of amorphous As2-xS3-xSbx thinfilms.
Ramakanta Naik, R.Ganesan and K.S.Sangunni .
Thin Solid Films, 518, 5437 (2010)

Photoinduced optical changes in Sb/As2S3multilayered film and (As2S3)0.93Sb0.07film of equal thickness.
Ramakanta Naik, R.Ganesan, K.S.Sangunni
Journal of Alloys and Compounds, 505,249 (2010)

Temperature dependent optical constants of amorphous Ge2Sb2Te5thin films.
Vinod E. M.,Ramakanta Naik, A. P. A. Faiyas, R. Ganesan, K.S.Sangunni
Journal of Non-Crystalline Solids, 356, 2172 (2010)

Temperature dependent optical constants of amorphous Ge2Sb2Te5 thin films
E. M. Vinod, Ramakanta Naik, A. P. A. Faiyas, R. Ganesan, K.S.Sangunni
Journal of Non-Crystalline Solids, 356 (2010) 2172

Photo induced changes in the optical properties of thermally evaporated As40Se50Sb10 films
Ramakanta Naik, Arpitha Jain, E. M. Vinod, R. Ganesan, and K.S.Sangunni
Phys. Status Solidi C, 8 (2011) 2785

Optical properties change in amorphous (As2S3)0.87Sb0.13 thinfilms by photo and thermal induced process.
Ramakanta Naik, R.Ganesan ,K.S.Sangunni
Materials Chemistry and Physics, 125,505-509 (2011)

Photo-induced changes in the optical properties of thermally evaporated As40Se50Sb10 films.
Ramakanta Naik,Arpitha Jain,E.M.Vinod,R.Ganesan, K.S.Sangunni .
Physica Status Solidi C, 8, No-9, 2785 (2011)

Effect of Te addition on the optical properties of As2S3 thin film.
Ramakanta Naik,C.Kumar, R. Ganesan, K.S.Sangunni .
Materials Chemistry and Physics, 130,750 (2011)

Photo and thermal induced effects on (As2S3)0.85Sb0.15 amorphous thin films.
Ramakanta Naik, R.Ganesan, K.S.Sangunni .
Journal of Non-Crystalline Solids, 357, 2344 (2011)

Giant photo induced optical bleaching at room and liquid helium temperatures in Sb/As(2)S(3)multilayered films
Ramakanta Naik, K.V.Adarsh, R.Ganesan, K.S.Sangunni .
Optics Communications, 284, 5319 (2011)

Kinetics of photodarkening at room and liquid helium temperatures in a As(45)Se(55) thin film.
A.R.Barik, Ramakanta Naik, K.V.Adarsh, R.Ganesan.K.S.Sangunni , D.Zhao,Himanshu Jain
Physica Status Solidi C, 8,No-9, 2770 (2011)

Optical properties change in Sb(40)S(40)Se(20) thin films by light induced effect.
Ramakanta Naik, Sanjit K Parida, C. Kumar, R. Ganesan,K.S.Sangunni .
Journal of Alloys and Compounds, 522, 172 (2012)

Compositional dependence optical properties of As(40)Se(60-x)Sb(x) thin films.
Ramakanta Naik, Arpitha Jain, R.Ganesan,K.S.Sangunni
Thin Solid Films, 520, 2510 (2012)

Effect of selenium addition on the GeTe phase change memory alloys
E. M. Vinod, A. K. Singh, R. Ganesan, K.S.Sangunni ,
Journal of Alloys and Compounds, 537 (2012) 127

Signatures of Ge2Sb2Te5 film at structural transitions
E. M. Vinod, Ramakanta Naik, R. Ganesan,K.S.Sangunni
Journal of Non-Crystalline Solids, 358 (2012) 2927

Coexistence of fast photodarkening and slow photobleaching in Ge19As21Se60 thin films
Pritam Khan, A. R. Barik, E. M. Vinod, K.S.Sangunni , H. Jain, and K. V. Adarsh,
Optics Express, 20 (2012) 12416

The Effect of Se Doping on Spectroscopic and Electrical properties of GeTe
E. M. Vinod, K.S.Sangunni
Thin Solid films, 550 (2013) 569.

Crossover from Photo darkening to Photo bleaching in a-GexSe100-x thin films
Rakesh Ranjan Kumar, A. R. Barik, E. M. Vinod, Mukund Bapna, K.S.Sangunni , and K.V. Adarsh,
Optics Letters, 38 (2013) 1682.





Conferences

Short range order in Cu28As40Se32 glass
Ashwani Kumar, A.V. Pimpale, N. Ramesh Rao, K.S. Sangunni, E.S.R. Gopal and V. Chernov
Proc. D.A.E. Solid State Phys. Symp. 38C (Calcutta, India, 1995) p. 221.

Network connectivity in GeSe2 glass
N. Ramesh Rao, B.A. Dasannacharya, K.S.Sangunni and ESR. Gopal
Proc.DAE. Solid State Phys.Symp.38C (Calcutta,India 1995)p.236.

EXAFS studies of short range order in CuAsSe glasses
Ashwani Kumar, V. Chernov, N. Ramesh Rao, K.S.Sangunni and E.S.R.Gopal,
Presented at XAFS-IX int. conf., ESRF, Grenoble (August 1996).

High pressure resistivity studies on Cu-Ge-Te glasses
K. Ramesh, S. Asokan, K.S.Sangunni and E.S.R. Gopal,
High Pressure Science & Technology, edited by W.A.Trzeciakowski (World Scientific, Singapore, 1996) p.776 - 778.

Crystallization Kinetics of Ge20Se60Te20
M.K.Rabinal, N.Ramesh Rao,K.S.Sangunni,S.Asohan and E.S.R.Gopal
Proc of SSP Symposium (Banaras) p155

Direct evidence for discrete gap levels in Chalcogenide glasses
N.Asha Bhat and K.S.Sangunni
International workshop on Amorphous and Nanostructured chalcogenids.Bucharest - Romania (2001)

PL due to discrete gap levels in some chalcogenide glasses- A configurational coordinate diagram illustration
N.Asha Bhat and K.S.Sangunni
Mat.Rs.Soc.Symp.Proc.Vol 667 (2001) G3.4.1




Group



Technical support
Dr.K.Ramesh Msc.,Ph.D
Dr.R.Ganesan Msc.,Ph.D


Recent Ph.D thesis awarded

Dr.N.Ramesh Rao
Dr.K.Ramesh
Dr.Asha N.Bhat
Dr.R.Ganesan
Dr.Adarsh.K.V
Dr.Ramakantha Naik
Dr.Vinod.E.M