Biography

I obtained BSc Hons degree in Physics from University of Jaffna, Sri Lanka in 2010, and MSc by Research and PhD in Condensed Matter Physics from University of Nottingham in 2012 and 2015, respectively. Following my PhD, I worked as a postdoctoral researcher for 3 years at University of Nottingham and 18 months at University of Manchester. I was appointed as a Lecturer in Physics at Keele University in October 2019.

Research and scholarship

I am interested in studying the fundamental properties and applications of novel 2D materials. My research focuses on the production, characterization and exploitation of 2D materials, especially III-VI van der Waals layered materials. I am collaborating with the University of Nottingham, the University of Manchester and the National Physics Laboratory for various projects.

Synthesis

I have successfully developed a physical vapour deposition method to grow beta-In2Se3 on different substrates (SiO2, mica and graphite) and different In-Se compounds on GaSe crystal (N. Balakrishnan et al., 2016, 2018). Currently I am focussing to develop different band alignment and potential profiles by growing III-VI layers on different layered semiconductors. By combining materials with different band gap energies enable to fabricate different optoelectronic devices, including multi-colour solar cells.

Optoelectronics

The integration of 2D layered semiconductors with graphene to form heterostructure devices offers new routes to the fabrication of optoelectronic devices such as light emitting diodes (LEDs), fast and ultrasensitive photodetectors, etc. I fabricate van der Waals heterostructure devices to study their optical, electronic and optoelectronic properties (N. Balakrishnan et al., 2014, 2017).

Ferroelectrics

The miniaturization of ferroelectric devices offers prospects for non-volatile memories, low-power electrical switches and emerging technologies beyond existing Si-based integrated circuits. An emerging class of ferroelectrics is based on van der Waals 2D materials with potential for nano-ferroelectrics. I am interested to study the ferroelectric properties of In2Se3 and CuInP2S6 (S. Xie et al., 2021).

Thermoelectrics

Van der Waals 2D materials offer a versatile platform to tailor heat transfer due to their high surface-to-volume ratio and mechanical flexibility. Recently, we studied the nanoscale thermal properties of 2D InSe layers by scanning thermal microscopy (D. Buckley et al., 2021). I am interested to fabricate and characterise thermoelectric devices.

Twistronics

The stacking method of 2D materials has another degree of freedom; the individual layers can be aligned with different angles with respect to each other, which creates a Moiré pattern. The twist angle can be acts as a knob to tune the electronic properties of the stack. Recently, we studied the electronic transport properties of twisted monolayer–bilayer graphene heterostructure. We observed the formation of van Hove singularities that are highly tunable by changing either the twist angle or external electric field and can cause strong correlation effects under optimum conditions (S. Xu et al., 2021). I am interested to explore the other 2D materials twisted heterostructures.

Other research interests

  1. Energy storage devices (batteries, supercapacitors, hydrogen storage).
  2. Strain engineering of 2D materials.

Teaching

Year 1
Oscillations and Waves

Year 2
Applied Physics and Emerging Technologies

Selected Publications

  • Xu S, Al Ezzi MM, Balakrishnan N, Garcia-Ruiz A, Tsim B, Mullan C, Barrier J, Xin N, Piot BA, Taniguchi T, Watanabe K, Carvalho A, Mishchenko A, Geim AK, Fal’ko VI, Adam S, Neto AHC, Novoselov KS, Shi Y. Tunable van Hove singularities and correlated states in twisted monolayer–bilayer graphene. Nature Physics. doi> link> full text>
  • Buckley D, Kudrynskyi ZR, Balakrishnan N, Vincent T, Mazumder D, Castanon E, Kovalyuk ZD, Kolosov O, Kazakova O, Tzalenchuk A, Patane A. 2021. Anomalous Low Thermal Conductivity of Atomically Thin InSe Probed by Scanning Thermal Microscopy. ADVANCED FUNCTIONAL MATERIALS, Article ARTN 2008967, vol. 31(11). link> doi> full text>
  • Balakrishnan N, Steer ED, Smith EF, Kudrynskyi ZR, Kovalyuk ZD, Eaves L, Patanè A, Beton PH. Epitaxial growth of γ-InSe and α, β, and γ-In2Se3 on ε-GaSe. 2D Materials, 035026, vol. 5(3). doi> full text>
  • Balakrishnan N, Kudrynskyi ZR, Smith EF, Fay MW, Makarovsky O, Kovalyuk ZD, Eaves L, Beton PH, Patanè A. Engineering p–n junctions and bandgap tuning of InSe nanolayers by controlled oxidation. 2D Materials, 025043, vol. 4(2). doi> full text>
  • Balakrishnan N, Staddon CR, Smith EF, Stec J, Gay D, Mudd GW, Makarovsky O, Kudrynskyi ZR, Kovalyuk ZD, Eaves L, Patanè A, Beton PH. Quantum confinement and photoresponsivity ofβ-In2Se3nanosheets grown by physical vapour transport. 2D Materials, 025030, vol. 3(2). doi> full text>

Full Publications Listshow

Journal Articles

  • Xie S, Dey A, Yan W, Kudrynskyi ZR, Balakrishnan N, Makarovsky O, Kovalyuk ZD, Castanon EG, Kolosov O, Wang K, Patane A. 2021. Ferroelectric semiconductor junctions based on graphene/In2Se3/graphene van der Waals heterostructures. 2D MATERIALS, Article ARTN 045020, vol. 8(4). link> doi> full text>
  • Xu S, Al Ezzi MM, Balakrishnan N, Garcia-Ruiz A, Tsim B, Mullan C, Barrier J, Xin N, Piot BA, Taniguchi T, Watanabe K, Carvalho A, Mishchenko A, Geim AK, Fal’ko VI, Adam S, Neto AHC, Novoselov KS, Shi Y. Tunable van Hove singularities and correlated states in twisted monolayer–bilayer graphene. Nature Physics. doi> link> full text>
  • Buckley D, Kudrynskyi ZR, Balakrishnan N, Vincent T, Mazumder D, Castanon E, Kovalyuk ZD, Kolosov O, Kazakova O, Tzalenchuk A, Patane A. 2021. Anomalous Low Thermal Conductivity of Atomically Thin InSe Probed by Scanning Thermal Microscopy. ADVANCED FUNCTIONAL MATERIALS, Article ARTN 2008967, vol. 31(11). link> doi> full text>
  • Berenguer F, Pettinari G, Felici M, Balakrishnan N, Clark JN, Ravy S, Patané A, Polimeni A, Ciatto G. 2020. Imaging shape and strain in nanoscale engineered semiconductors for photonics by coherent x-ray diffraction. Communications Materials, Article 19, vol. 1(1). doi> link> full text>
  • Backes C, Abdelkader AM, Alonso C, Andrieux-Ledier A, Arenal R, Azpeitia J, Balakrishnan N, Banszerus L, Barjon J, Bartali R, Bellani S, Berger C, Berger R, Ortega MMB, Bernard C, Beton PH, Beyer A, Bianco A, Bøggild P, Bonaccorso F, Barin GB, Botas C, Bueno RA, Carriazo D, Castellanos-Gomez A, Christian M, Ciesielski A, Ciuk T, Cole MT, Coleman J, Coletti C, Crema L, Cun H, Dasler D, De Fazio D, Díez N, Drieschner S, Duesberg GS, Fasel R, Feng X, Fina A, Forti S, Galiotis C, Garberoglio G, García JM, Garrido JA, Gibertini M, Gölzhäuser A, Gómez J, Greber T, Hauke F, Hemmi A, Hernandez-Rodriguez I, Hirsch A, Hodge SA, Huttel Y, Jepsen PU, Jimenez I, Kaiser U, Kaplas T, Kim H, Kis A, Papagelis K, Kostarelos K, Krajewska A, Lee K, Li C, Lipsanen H, Liscio A, Lohe MR, Loiseau A, Lombardi L, Francisca López M, Martin O, Martín C, Martínez L, Martin-Gago JA, Ignacio Martínez J, Marzari N, Mayoral Á, McManus J, Melucci M, Méndez J, Merino C, Merino P, Meyer AP, Miniussi E, Miseikis V, Mishra N, Morandi V, Munuera C, Muñoz R, Nolan H, Ortolani L, Ott AK, Palacio I, Palermo V, Parthenios J, Pasternak I, Patane A, Prato M, Prevost H, Prudkovskiy V, Pugno N, Rojo T, Rossi A, Ruffieux P, Samorì P, Schué L, Setijadi E, Seyller T, Speranza G, Stampfer C, Stenger I, Strupinski W, Svirko Y, Taioli S, Teo KBK, Testi M, Tomarchio F, Tortello M, Treossi E, Turchanin A, Vazquez E, Villaro E, Whelan PR, Xia Z, Yakimova R, Yang S, Yazdi GR, Yim C, Yoon D, Zhang X, Zhuang X, Colombo L, Ferrari AC, Garcia-Hernandez M. 2020. Production and processing of graphene and related materials. 2D Materials, 022001, vol. 7(2). doi> link> full text>
  • Balakrishnan N, Steer ED, Smith EF, Kudrynskyi ZR, Kovalyuk ZD, Eaves L, Patanè A, Beton PH. Epitaxial growth of γ-InSe and α, β, and γ-In2Se3 on ε-GaSe. 2D Materials, 035026, vol. 5(3). doi> full text>
  • Di Paola DM, Velichko AV, Bomers M, Balakrishnan N, Makarovsky O, Capizzi M, Cerutti L, Baranov AN, Kesaria M, Krier A, Taliercio T, Patanè A. 2018. Optical Detection and Spatial Modulation of Mid-Infrared Surface Plasmon Polaritons in a Highly Doped Semiconductor. Advanced Optical Materials, 1700492, vol. 6(3). doi> full text>
  • Balakrishnan N, Kudrynskyi ZR, Smith EF, Fay MW, Makarovsky O, Kovalyuk ZD, Eaves L, Beton PH, Patanè A. Engineering p–n junctions and bandgap tuning of InSe nanolayers by controlled oxidation. 2D Materials, 025043, vol. 4(2). doi> full text>
  • Balakrishnan N, Staddon CR, Smith EF, Stec J, Gay D, Mudd GW, Makarovsky O, Kudrynskyi ZR, Kovalyuk ZD, Eaves L, Patanè A, Beton PH. Quantum confinement and photoresponsivity ofβ-In2Se3nanosheets grown by physical vapour transport. 2D Materials, 025030, vol. 3(2). doi> full text>
  • Ciatto G, Pettinari G, Balakrishnan N, Berenguer F, Patane A, Birindelli S, Felici M, Polimeni A. 2015. Synchrotron x-ray diffraction study of micro-patterns obtained by spatially selective hydrogenation of GaAsN. APPLIED PHYSICS LETTERS, Article ARTN 051905, vol. 106(5). link> doi> full text>
  • Balakrishnan N, Kudrynskyi ZR, Fay MW, Mudd GW, Svatek SA, Makarovsky O, Kovalyuk ZD, Eaves L, Beton PH, Patane A. 2014. Room Temperature Electroluminescence from Mechanically Formed van der Waals III-VI Homojunctions and Heterojunctions. ADVANCED OPTICAL MATERIALS, 1064-1069, vol. 2(11). link> doi> full text>
  • Balakrishnan N, Pettinari G, Makarovsky O, Hopkinson M, Patane A. 2014. Tunable spectral response by hydrogen irradiation of Ga(AsN) superlattice diodes. APPLIED PHYSICS LETTERS, Article ARTN 242110, vol. 104(24). link> doi> full text>
  • Pettinari G, Balakrishnan N, Makarovsky O, Campion RP, Polimeni A, Capizzi M, Patane A. 2013. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode. APPLIED PHYSICS LETTERS, Article ARTN 241105, vol. 103(24). link> doi> full text>
  • Balakrishnan N, Pettinari G, Makarovsky O, Turyanska L, Fay MW, De Luca M, Polimeni A, Capizzi M, Martelli F, Rubini S, Patane A. 2012. Band-gap profiling by laser writing of hydrogen-containing III-N-Vs. PHYSICAL REVIEW B, Article ARTN 155307, vol. 86(15). link> doi> full text>
  • Balakrishnan N, Patane A, Makarovsky O, Polimeni A, Capizzi M, Martelli F, Rubini S. 2011. Laser writing of the electronic activity of N- and H-atoms in GaAs. APPLIED PHYSICS LETTERS, Article ARTN 021105, vol. 99(2). link> doi> full text>

Other

  • Balakrishnan N. Indium Selenides: From the growth to the exploitation. https://meetx.eventsair.com/graphene-week-2021/official-program. Graphene Flagship. full text>
  • Balakrishnan N, Shi Y, Xu S, Al Ezzi MM, Garcia-Ruiz A, Tsim B, Mullan C, Barrier J, Xin N, Piot BA, Taniguchi T, Watanabe K, Carvalho A, Mishchenko A, Geim AK, Fal’ko VI, Adam S, Castro Neto AH, Novoselov KS. Tunable van Hove singularities and correlated states in twisted monolayer–bilayer graphene. https://meetx.eventsair.com/graphene-week-2021/official-program. Graphene Flagship. full text>
  • Balakrishnan N. Formative Assessment Encourages Active Learning by Challenging Students. IOP Conferences. IOP. link> link> full text>
  • Balakrishnan N, Steer E, Smith E, Kudrynsky Z, Kovalyuk Z, Eaves L, Patanè A, Beton P. Epitaxial growth of γ-InSe and α, β, and γ-In2Se3 on ε-GaSe. woi.chemie.uni-leipzig.de. doi> link> full text>
  • Balakrishnan N, Kudrynskyi Z, Kovalyuk Z, Eaves L, Beton P, Patanè A. From the growth to the exploitation of two-dimensional InxSey. www.graphene-flagship.eu. full text>
  • Balakrishnan N. NOVEL APPROACHES TO THE FABRICATION OF NANOSCALE DEVICES.
  • Balakrishnan N, Mudd G, Svatek S, Ren T, Patene A, Makarovsky O, Eaves L, Beton P, Kovalyuk Z, Lashkarev GV, Kudrynskyi Z, Dmitriev AI. Tuning the Bandgap of Exfoliated InSe Nanosheets by Quantum Confinement. ICPS. doi> full text>
  • Balakrishnan N. Laser Writing of the Electronic Activity of Nitrogen and Hydrogen Atoms in Gallium Arsenide. full text>
Accreditation logo for Athena Swan Bronze