Member in Lab

Self Introduction

    Microgravity, Materials Science, Materials Engineering, Space Applications

  • I am joined as JAXA’s Aerospace Project Research Associate in Prof. Inatomi’s lab by this April 2017. I was born and brought up from Kalavai, a small town in Tamil Nadu, India. I did dual Ph.D. degrees from Anna University, India (Science) and Shizuoka University, Japan (Engineering). I availed Monbukagakusho:MEXT fellowship from the Government of Japan to do doctoral course from Shizuoka University. During My Ph.D. in India, I synthesized a new material CuCdS2 for the first time and found its properties were suitable for photovoltaic applications.
  • I am working on microgravity experiments since I joined for my Ph.D. at Shizuoka University. I have analysed the first ternary alloy InGaSb that was grown under microgravity condition using the space platform ‘International Space Station’. The microgravity experimental results were published as 2 consecutive articles in the years 2015 and 2016 in a nature partner journal ‘npj Microgravity’. I proposed a model to explain the higher dissolution of GaSb along (111)B than (111)A (Sb and Ga faces of GaSb (111)) under microgravity. Also I have analysed the thermoelectric properties of InxGa1-xSb crystals for the first time. The thermal conductivity of GaSb and InSb binaries were reduced in InxGa1-xSb ternaries, successfully. To explain the reduced thermal conductivity, I proposed a model that explains the phonon scattering by defects in InxGa1-xSb ternaries. The research findings during my Ph.D. were published in refereed international journals. So far 13 research articles were published, 22 papers were presented in Domestic/international conferences and 3 awards were obtained.
  • I have obtained ‘Young Researcher Award’ for the best presentation at Inter Academia – 13th international conference on global research and education that was held during September 2014 in Latvia, Europe. The Deans award for Graduate School of Science and Technology, Shizuoka University in the year 2016 was given to me for outstanding work in scholarly research during Ph.D.
  • At present I joined in the Department of Interdisciplinary Space Sciences, Institute of Space and Austronautical Sciences, Japan Aerospace Exploration Agency, Sagamihara, Japan. I continue my work in the fields of ‘Microgravity Materials Science and Materials Engineering for Space Applications’.

 

List of Publications (Peer reviewed)

  1. [Link] Velu Nirmal Kumar, Yasuhiro Hayakawa, Mukannan Arivanandhan, Govindasamy Rajesh, Tadanobu Koyama, Yoshimi Momose, Tetsuo Ozawa, Yasunori Okano, and Yuko Inatomi: “Orientation dependent dissolution and growth properties of InGaSb ternary alloys under microgravity on board the International Space Station”, Journal of Crystal Growth 496-497 (2018) pp. 15-17.
  2. [Link] V. Nirmal Kumar, R. Suriakarthick, Y. Hayakawa, R. Gopalakrishnan: "Enhanced electrical and optical properties of CdS:Na thin films by photochemical deposition", Journal of Crystal Growth 468 (2017) pp. 208-211.
  3. [Link] Y. Hayakawa, V. Nirmal Kumar, M. Arivanandhan, G. Rajesh, T. Koyama, Y. Momose, K. Sakata, T. Ozawa, Y. Okano, Y. Inatomi: "Effects of gravity and crystal orientation on the growth of InGaSb ternary alloy semiconductors -experiments at the international space station and on Earth", International Journal of Microgravity Science and application 34 (2017) pp. 340111 1-12.
  4. [Link] V. Nirmal Kumar, M. Arivanandhan, T. Koyama, H. Udono, Y. Inatomi, Y. Hayakawa: "Effects of varying indium composition on the thermoelectric properties of InxGa1-xSb ternary alloys", Applied Physics A 122 (2016) pp. 885 1-9.
  5. [Link] V. Nirmal Kumar, M. Arivanandhan, G. Rajesh, T. Koyama, Y. Momose, K. Sakata, T. Ozawa, Y. Okano, Y. Inatomi, Y. Hayakawa: "Investigation of directionally solidified InGaSb ternary alloys from Ga and Sb faces of GaSb(111) under prolonged microgravity at the International Space Station", nature partner journal - npj Microgravity 2 (2016) pp. 16026.
  6. [Link] J. Yu, Y. Liu, X. Pan, H. Zhao, V. Nirmal Kumar, M. Arivanandhan, Y. Momose, Y. Hayakawa, X. Zhang, X. Luo, Y. Okano, Y. Inatomi: "A Review on InGaSb Growth under Microgravity and Terrestrial Conditions Towards Future Crystal Growth Project Using Chinese Recovery Satellite SJ-10", Microgravity Science and Technology 28 (2016) pp. 143-154.
  7. [Link] S. Karuppusamy, K. Dinesh Babu, V. Nirmal Kumar, R. Gopalakrishnan: "Thermal kinetic and dielectric parameters of acenapthene crystal grown by vertical Bridgman technique", Applied Physics A 122 (2016) pp. 498-1-8.
  8. [Link] Y. Inatomi, K. Sakata, M. Arivanandhan, G. Rajesh, V. Nirmal Kumar, T. Koyama, Y. Momose, T. Ozawa, Y. Okano and Y. Hayakawa: "Growth of InxGa1-xSb alloy semiconductor at the International Space Station (ISS) and comparison with terrestrial experiments", nature partner journal - npj Microgravity 1 (2015) pp. 15011.
  9. [Link] R. Suriakarthick, V. Nirmal Kumar, R.Gopalakrishnan: "Effect of substrate temperature on copper antimony sulphide thin films from thermal evaporation", Journals of Alloys and Compounds 651 (2015) pp. 423-433.
  10. [Link] V. Nirmal Kumar, R. Suriakarthick, S,Karuppasamy, Mukul Gupta, Y. Hayakawa, R. Gopalakrishnan: "Effect of precursor concentration on the properties and tuning of conductivity between p-type and n-type of Cu1-xCdxS2 thin films deposited by single step solution process as a novel material for photovoltaic application", RSC Advances 5 (2015) pp. 23015-23021,
  11. [Link] V. Nirmal Kumar, R. Suriakarthick, Y. Hayakawa, Shamima Hussain, G. M. Bhalerao, Mukul Gupta, Vasant Sathe, R. Gopalakrishnan: "Deposition of CuCdS2 thin film by single step solution process at low temperature as a novel absorber for photovoltaic applications", Superlattices and Microstructures 76 (2014) pp. 125-134.
  12. [Link] R. Suriakarthick, V. Nirmal Kumar, T. S Shyju, R, Gopalakrishnan: "Investigation on post annealed copper sulfide thin films from photochemical deposition technique", Materials Science in Semiconductor Processing 26 (2014) pp. 155-161.
  13. [Link] R. Suriakarthick, V. Nirmal Kumar, R. Indirajith, T.S. Shyju, R. Gopalakrishnan: "Photochemically deposited and post annealed copper indium disulphide thin films", Superlattices and Microstructures 75 (2014) pp. 667-679.
  14. [Link] V. Nirmal Kumar, R. Suriakarthick, T. S. Shyju and R. Gopalakrishnan: "Deposition of CdS thin films by chemical bath and photochemical deposition methods and its characterization", AIP Conference Proceedings 1536 (2013) pp. 347-348.

Paper Presented in International Conferences

  1. V. Nirmal Kumar, R. Suryakarthick, R. Gopalakrishnan, Y. Hayakawa, "Enhanced Electrical and Optical Properties of CdS:Na Thin Films by Photochemical Deposition", The 18th International Conference on Crystal Growth and Epitaxy, 2016, 7-12, August 2016, Nagoya, Japan.
  2. V. Nirmal Kumar, M. Arivanandhan, G. Rajesh, T. Koyama, K. Sakata, Y. Momose, T. Ozawa, Y. Okano, Y. Inatomi, Y. Hayakawa, "Gravity effect on the properties of InxGa1-xSb ternary alloys grown at the International Space Station", IEICE Technical Committee on Electron Device, 19-20 May 2016, Shizuoka University, Hamamatsu, Japan.
  3. V. Nirmal Kumar, R. Suryakarthick, R. Gopalakrishnan, Y. Hayakawa, "Physical properties of novel CuxCd1-xS2 compound semiconductor thin films by single step solution process for low cost photovoltaic devices", The 14th International Conference on Global Research and Education - Inter Academia 2015, 28-30, September 2015, Hamamatsu, Japan.
  4. V. Nirmal Kumar, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi,Y. Okano, Y. Hayakawa et al., "Growth properties of InGaSb ternary alloys under microgravity and normal gravity conditions", The Joint Conference of 6th International Symposium on Physical Sciences in Space - ISPS-6 and ITTW 2015, 14-18, September 2015, Kyoto, Japan.
  5. V. Nirmal Kumar, R. Suryakarthick, R. Gopalakrishnan, Y. Hayakawa, "Physical properties of novel Cu1-xCdxS2 thin films grown by chemical bath deposition method for low cost solar cell", The 76th JSAP autumn meeting, 13-16, September 2015, Nagoya, Japan.
  6. V. Nirmal Kumar, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi, Y. Okano, Y. Hayakawa et al. "Properties of InGaSb crystals grown under microgravity (μG) at International Space Station and normal gravity (1G) conditions", The 62nd JSAP spring meeting, 11-14, March 2015, Tokai University, Shonan campus, Japan
  7. V. Nirmal Kumar, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi, Y. Okano, Y. Hayakawa et al. "Growth process of InGaSb under microgravity and normal gravity conditions", 2015 International Symposium toward the Future of Advanced Researches in Shizuoka University, 27-28, January, 2015, Shizuoka University, Hamamatsu, Japan.
  8. V. Nirmal Kumar, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi, Y. Okano, Y. Hayakawa et al. "Effect of gravity on InGaSb crystal growth - Microgravity at International Space Station and 1G conditions", Japan Society of Microgravity Application 28th academic lecture - JASMAC-28, 26-28, November, 2014, Egress Himeji, Himeji, Hyogo prefecture, Japan.
  9. V. Nirmal Kumar, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi, Y. Okano, Y. Hayakawa et al. "Growth and properties of InGaSb alloy semiconductor crystals grown under microgravity and 1G conditions", The 75th JSAP autumn meeting, 17-20, September, 2014, Sapporo campus, Hokkaido University, Hokkaido, Japan.
  10. V. Nirmal Kumar, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi, Y. Okano, Y. Hayakawa et al., "Growth of InGaSb alloy semiconductor crystal under 1G condition as a preliminary study for microgravity experiment at International Space Station", Inter Academia-13th International conference on global research and education, 10-12 September 2014, Riga Technical Institute, Riga, Latvia, Europe.
  11. V. Nirmal Kumar, Y. Katsumata, M. Arivanandhan, T. Koyama, Y. Momose, Y. Inatomi, Y. Okano, Y. Hayakawa, "Ground-based experiments for crystal growth of InGaSb", The 1st Japan-China Workshop on Microgravity Sciences, 9th February 2014, RIE, Shizuoka University, Hamamatsu, Japan.
  12. V. Nirmal Kumar, R. Suryakarthick, T.S. Shyju, R. Gopalakrishnan, "Deposition of CdS thin films by chemical bath and photochemical deposition methods and their characterization", "International conference on Recent trends in Applied Physics and Materials science", held during 1-2 February, 2013, at College of engineering and technology, Bikaner, Rajasthan.
  13. V. Nirmal Kumar, R. Suryakarthick, R. Gopalakrishnan, "Effect of Annealing on the deposition of CdS thin films by chemical bath and photochemical deposition methods", "Indo-German workshop on advanced materials for future energy requirements", held during 29 November - 1 December 2012, at University of Delhi, New Delhi.

Paper Presented in National Conferences

  1. V. Nirmal Kumar, Y. Hayakawa, M. Arivanandhan, G. Rajesh, T. Koyama, Y. Momose, K. Sakata, T. Ozawa, Y. Okano, Y. Inatomi, "Growth process of InGaSb ternary alloys from (111)A and (111)B planes of GaSb under microgravity on board the International Space Station", JASMAC-29: Microgravity Applied Society The 29th Academic Lecture, 25-27 October 2017, College of Engineering, Nihon University, Tsudanuma, Japan
  2. V. Nirmal Kumar, Y. Hayakawa, M. Arivanandhan, G .Rajesh, T. Koyama, Y. Momose, K. Sakata, T. Ozawa, Y. Okano, Y. Inatomi, "Orientation dependent dissolution and growth process of InGaSb ternary alloys under microgravity on board the International Space Station", JACG - The 40th Crystal Growth Discussion, 30 August - 1 September 2017, Hamanako Royal Hotel, Hamamatsu, Shizuoka, Japan.
  3. V. Nirmal Kumar, M. Arivanandhan, G. Rajesh, T. Koyama, K. Sakata, Y. Momose, T. Ozawa, Y. Okano, Y. Inatomi, Y. Hayakawa, "Growth properties of InGaSb ternary alloys from Ga and Sb faces of GaSb (111) under microgravity on board the International Space Station", JST SAKURA and SSSV Seminar Program, 31 August, 2016 at Shizuoka University, Hamamatsu, Japan.
  4. V. Nirmal Kumar, R. Suriakarthick, R. Gopalakrishnan, Y. Hayakawa, "Novel ternary compound Cu1-xCdxS2 thin films by single step solution process for low cost photovoltaic devices", The 17th Takayanagi Kenjiro memorial symposium, 17-18 November 2015, Shizuoka University, Hamamatsu, Japan.
  5. V.Nirmal Kumar, M. Arivanandhan, G. Rajesh, T. Koyama, K. Sakata, Y. Momose, T. Ozawa, Y. Okano, Y. Inatomi, Y. Hayakawa, "Growth properties of InGaSb under normal and microgravity condition at International Space Station", JST SAKURA and SSSV Seminar Program, 3 September, 2015, Shizuoka University, Hamamatsu, Japan.
  6. V. Nirmal Kumar, R. Gopalakrishnan, "Deposition and characterization of copper cadmium sulphide (CuCdS2) thin films by chemical bath deposition method", XVII National Seminar on Crystal Growth in association with Indian Association for Crystal Growth, 9-11, January 2013, Anna University, Chennai.
  7. V. Nirmal Kumar, T.S. Shyju, R. Gopalakrishnan, "Deposition of CdS thin films by Photo Chemical and Chemical Bath Deposition methods and its characterization", DAE BRNS 6th National Symposium on Pulsed Laser Deposition of Thin Films and Nanostructured Materials, 9-11, November 2011, Materials Research Centre, Indian Institute of Science, Bengaluru.

Invited Lectures

  1. Y. Hayakawa, Y. Inatomi, V. Nirmal Kumar M. Arivanandhan, G. Rajesh, T. Koyama, K. Sakata, Y. Momose, T. Ozawa, Y. Okano, ‘Effect of gravity on the dissolution and , The 16th Takayanagi growth process of InGaSb ternary alloy bulk semiconductor’ Kenjiro memorial symposium, 11–12 November 2014, Shizuoka University, Hamamatsu, Japan.
  2. Y. Hayakawa, V. Nirmal Kumar M. Arivanandhan, G. Rajesh, T. Koyama, K. Sakata, ,Y. Momose, T. Ozawa, Y. Okano, Y. Inatomi, ‘Microgravity experiment of InGaSb , 60th DAE – Solid State alloy semiconductor crystals at International Space Station’ Physics Symposium, 21 – 25 December 2015, Amity University, Noida, U.P, India.
  3. Y. Hayakawa, V. Nirmal Kumar M. Arivanandhan, G. Rajesh, T. Koyama, K. Sakata, Y. Momose, T. Ozawa, Y. Okano, Y. Inatomi, ‘Semiconductor crystal growth , The 3rd Japan-China Workshop on Materials experiments under microgravity’ Microgravity Science in Space, 25 – 28 March 2016, University of the Ryukyus, Okinawa, Japan.

Awards / Honors

  1. Dean’s Award (The best Ph.D. thesis) for Graduate School of Science and Technology by Shizuoka University, Japan, for outstanding work in scholarly research during Ph.D. (16th September 2016).
  2. Young Researcher Award for the best oral presentation on “Growth of InGaSb alloy semiconductor crystal under 1G condition as a preliminary study for microgravity experiment at International Space Station”, Inter Academia -13th International conference on global research and education, Riga Technical Institute, Riga, Latvia (10-12 September 2014).
  3. Mori-Fighting Spirit Award for the best presentation on “Effect of gravity on InGaSb crystal growth - Microgravity at International Space Station and 1G conditions”, Japan Society of Microgravity Application 28th academic lecture –JASMAC-28, Egress Himeji, Himeji, Japan (26-28 November 2014).
  4. Monbukagakusho:MEXT fellowship for research student by Ministry of Education Culture, Sports, Science and Technology, Japan for 3 years (1st October 2013 to 30th September 2016) to do research. (Research field: Growth and analyses of InGaSb crystal under microgravity condition at the international space station)