PUBLICATIONS

Journal Publications

Commentary & Reviews

Book & Book Chapters

Patents & Patent Applications


Jump to: Submitted, 2017, 2016, 2015, 2014 and prior

Submitted

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2017

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2016

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A new system for sodium flux growth of bulk GaN. Part II: in situ investigation of growth processes
P. Von Dollen, S. Pimputkar, M. Abo Alreesh, S. Nakamura, and J. S. Speck
J. Cryst. Growth, 456 (2016) 67-72, DOI: 10.1016/j.jcrysgro.2016.08.018

A new system for sodium flux growth of bulk GaN. Part I: System Development
P. Von Dollen, S. Pimputkar, M. Abo Alreesh, H. Albrithen, S. Suihkonen, S. Nakamura, and J. S. Speck
J. Cryst. Growth, 456 (2016) 58-66, DOI: 10.1016/j.jcrysgro.2016.07.044

On the solubility of gallium nitride in supercritical ammonia-sodium solutions
S. Griffiths, S. Pimputkar, J. S. Speck, and S. Nakamura
J. Cryst. Growth, 456 (2016) 5-14, DOI: 10.1016/j.jcrysgro.2016.08.041

Acidic ammonothermal growth of gallium nitride in a liner-free molybdenum alloy autoclave
T. F. Malkowski, S. Pimputkar, J. S. Speck, S. P. DenBaars, and S. Nakamura
J. Cryst. Growth, 456 (2016) 21-26, DOI: 10.1016/j.jcrysgro.2016.07.045

Basic ammonothermal GaN growth in molybdenum capsules
S. Pimputkar, J. S. Speck, and S. Nakamura
J. Cryst. Growth, 456 (2016) 15-20, DOI: 10.1016/j.jcrysgro.2016.07.034

Incorporation and effects of impurities in different growth zones within basic ammonothermal GaN
S. Sintonen, P. Kivisaari, S. Pimputkar, S. Suihkonen, T. Schulz, J. S. Speck, and S. Nakamura
J. Cryst. Growth, 456 (2016) 43-50, DOI: 10.1016/j.jcrysgro.2016.08.040

Infrared absorption of hydrogenated gallium-vacancies in ammonothermal GaN
S. Suihkonen, S. Pimputkar and J. S. Speck
Appl. Phys. Lett., 108 (2016) 202105, DOI: 10.1063/1.4952388

2015

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Stability of materials in supercritical ammonia solutions
S. Pimputkar, T. F. Malkowski, S. Griffiths, A. Espenlaub, S. Suihkonen, J. S. Speck, and S. Nakamura
J. Supercrit. Fluids, 110 (2016) 193–229, DOI: 10.1016/j.supflu.2015.10.020
In the news: Better materials promise LED’s at a fraction of the cost

Decomposition of supercritical ammonia and modeling of supercritical ammonia-nitrogen-hydrogen solutions with applicability towards ammonothermal conditions
S. Pimputkar and S. Nakamura
J. Supercrit. Fluids, 107 (2016) 17–30, DOI: 10.1016/j.supflu.2015.07.032
In the news: Advances in Engineering

Free electron concentration dependent sub-bandgap optical absorption characterization of bulk GaN crystals
S. Pimputkar, S. Suihkonen, M. Imade, Y. Mori, J. S. Speck, and S. Nakamura
J. Cryst. Growth, 423 (2015) 49–53, DOI: 10.1016/j.jcrysgro.2015.09.016

2014 and prior

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Improved growth rates and purity of basic ammonothermal GaN
S. Pimputkar, S. Kawabata, J. S. Speck, and S. Nakamura
J. Cryst. Growth, 403 (2014) 7–17, DOI: 10.1016/j.jcrysgro.2014.06.017

Surface morphology study of basic ammonothermal GaN grown on non-polar GaN seed crystals of varying surface orientations from m-plane to a-plane
S. Pimputkar, S. Kawabata, J. S. Speck, and S. Nakamura
J. Cryst. Growth, 368 (2013) 67–71, DOI: 10.1016/j.jcrysgro.2013.01.022

Development of gallium-nitride-based light-emitting diodes (LEDs) and laser diodes for energy-efficient lighting and displays
S. P. DenBaars, D. Feezell, K. Kelchner, S. Pimputkar, C.-C. Pan, C.-C. Yen, S. Tanaka, Y. Zhao, N. Pfaff, R. Farrell, M. Iza, S. Keller, U. Mishra, J. S. Speck, and S. Nakamura
Acta Mater., 61 (2013) 945–951, DOI: 10.1016/j.actamat.2012.10.042

Scintillators with potential to supersede lanthanum bromide
N. J. Cherepy, S. A. Payne, S. J. Asztalos, G. Hull, J. D. Kuntz, T. Niedermayr, S. Pimputkar, J. J. Roberts, R. D. Sanner, T. M. Tillotson, E. van Loef, C. M. Wilson, K. S. Shah, U. N. Roy, R. Hawrami, A. Burger, L. A. Boatner, W. S. Choong, and W. W. Moses
IEEE Trans. Nucl. Sci., 56 (2009) 873–880, DOI: 10.1109/TNS.2009.2020165


Jump to: Submitted, 2017, 2014 and prior

Submitted

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2017

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(PROGRESS REPORT) Defects in single crystalline ammonothermal gallium nitride
S. Suihkonen, S. Pimputkar, S. Sintonen, and F. Tuomisto
Adv. Electronic Mat., 3 (2017) 1600496, DOI: 10.1002/aelm.201600496

2014 and prior

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(HIGHLIGHT) Let there be light-with gallium nitride: The 2014 Nobel prize in physics
P. Von Dollen, S. Pimputkar and J. S. Speck
Angew. Chem. Int. Ed., 53 (2014) 13978–13980, DOI: 10.1002/anie.201410693

(COMMENTARY) Prospects for LED lighting
S. Pimputkar, J. S. Speck, S. P. DenBaars, and S. Nakamura
Nature Photon., 3 (2009) 180–182, DOI: 10.1038/nphoton.2009.32


Jump to: 2014

2014

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Ammonothermal growth of gallium nitride: overview and advances
S. Pimputkar
Lambert Academic Publishing (2014), ISBN: 3659566934


Jump to: 2011, 2009

2011

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Ammonothermal growth of group–III nitride crystals on seeds with at least two surfaces making an acute, right or obtuse angle with each other
S. Pimputkar, J. S. Speck, S. Nakamura, and S. Kawabata
Patent No. US9133564

2009

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Reactor designs for use in ammonothermal growth of group–III nitride crystals
S. Pimputkar, D. S. Kamber, J. S. Speck, and S. Nakamura
Patent No. US8641823

Using boron-containing compounds, gases, and fluids during ammonothermal growth of group–III nitride crystals
S. Pimputkar, D. S. Kamber, J. S. Speck, and S. Nakamura
Patent No. US8574525


Jump to: 2016, 2015, 2014, 2013, 2012, 2011, 2009

2016

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Solvothermal growth of single crystals using a single control temperature
S. Griffiths, S. Pimputkar, P. Von Dollen, and J. S. Speck
UC Case No. 2017-138

Group-III containing source material for bulk nitride solution growth
S. Griffiths, S. Pimputkar, P. Von Dollen, and J. S. Speck
UC Case No. 2017-137

System and apparatus of melt composition control for nitride crystal growth
P. Von Dollen, S. Pimputkar, D. Rehn, M. Aboalreesh, and J. Palmer
UC Case No. 2016-774

2015

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Enriching or maximizing ammonia concentrations in supercritical ammonia containing solutions
S. Pimputkar
UC Case No. 2016-244

System for high temperature solution crystal growth
P. Von Dollen, S. Pimputkar, G. Patterson, D. Rehn, J. S. Speck, M. Aboalreesh, and H. Albrithen
UC Case No. 2016-243

2014

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Use of molybdenum containing materials in the growth of group–III nitrides
S. Pimputkar, T. F. Malkowski and S. Nakamura
UC Case No. 2014-760

Growth of bulk gallium nitride crystals in a non-equilibrium growth environment
S. Pimputkar, S. Nakamura and J. S. Speck
UC Case No. 2014-134

Use of supercritical ammonia solutions containing alkali or alkali earth metals to remove oxides from group–III nitride containing source materials
S. Pimputkar, J. S. Speck and S. Nakamura
UC Case No. 2014-117

Use of ceramics and composite materials for the growth of group–III nitride bulk crystals
S. Pimputkar, S. Nakamura and J. S. Speck
UC Case No. 2014-116

Reactor vessels for ammonothermal and flux-based growth of group–III nitride crystals
S. Pimputkar, S. Nakamura and J. S. Speck
International Application No. WO2015031794A2

2013

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Apparatus used for the growth of group-III nitride crystals utilizing carbon fiber containing materials and group–III nitride grown therewith
S. Pimputkar, P. Von Dollen, S. Nakamura, and J. S. Speck
International Application No. WO2013155188A1

Crystal growth using non-thermal atmospheric pressure plasmas
P. Von Dollen, S. Pimputkar and J. S. Speck
International Application No. WO2013109854A1

2012

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Use of alkaline-earth metals to reduce impurity incorporation into a group–III nitride crystal grown using the ammonothermal method
S. Pimputkar, P. Von Dollen, J. S. Speck, and S. Nakamura
International Application No. WO2013063070A1

Method for improving the transparency and quality of group–III nitride crystals ammonothermally grown in a high purity growth environment
S. Pimputkar, S. Nakamura and J. S. Speck
International Application No. WO2013010121A1

Growth of bulk group–III nitride crystals after coating them with a group–III metal and an alkali metal
S. Pimputkar and J. S. Speck
International Application No. WO2013010118A1

Growing a group–III nitride crystal using a flux growth and then using the group–III nitride crystal as a seed for an ammonothermal re-growth
S. Pimputkar, S. Nakamura and J. S. Speck
International Application No. WO2013010117A1

2011

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Group–III nitride solar cells grown on high quality group–III nitride crystals mounted on foreign material
S. Pimputkar, S. Nakamura and S. P. DenBaars
US Application No. US20120103419

Group–III nitride crystal ammonothermally grown using an initially off-oriented non-polar or semi-polar growth surface of a group–III nitride seed crystal
S. Pimputkar, J. S. Speck and S. Nakamura
International Application No. WO2011115950A1

2009

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Addition of hydrogen and/or nitrogen containing compounds to the nitrogen-containing solvent used during the ammonothermal growth of group–III nitride crystals
S. Pimputkar, D. S. Kamber, J. S. Speck, and S. Nakamura
International Application No. WO2010053996A1

Group–III nitride monocrystal with improved purity and method of producing the same
D. S. Kamber, S. Pimputkar, M. Saito, S. P. DenBaars, J. S. Speck, and S. Nakamura
International Application No. WO2010053966A1

Controlling relative growth rates of different exposed crystallographic facets of a group–III nitride crystal during the ammonothermal growth of a group–III nitride crystal
S. Pimputkar, D. S. Kamber, J. S. Speck, and S. Nakamura
International Application No. WO2010053963A1

Novel vessel designs and relative placements of the source material and seed crystals with respect to the vessel for the ammonothermal growth of group–III nitride crystals
S. Pimputkar, D. S. Kamber, J. S. Speck, and S. Nakamura
International Application No. WO2010053964A1

Group–III nitride monocrystal with improved crystal quality grown on an etched-back seed crystal and method of producing the same
S. Pimputkar, D. S. Kamber, M. Saito, S. P. DenBaars, J. S. Speck, and S. Nakamura
International Application No. WO2010053977A1