People

Broadly, my team's research goal is Development of Neuromorphic Computing hardware based on low thermal budget and sustainable materials and processes. To achieve this goal, we work on different sub-topics ranging from materials, devices, modelling, design, high-end fabrication and system level integration.

• Modelling Ferroelectric Hysteresis of HZO Capacitor with Jiles-Atherton Model for Non-Volatile Memory Applications, Ella Paasio, Mika Prunnila, Sayani Majumdar, IEEE 12th Non-Volatile Memory Systems and Applications Symposium (NVMSA), Niigata, Japan, pp.1, 2023. doi: 10.1109/NVMSA58981.2023.00019.
• Back-end and Flexible Substrate Compatible Analog Ferroelectric Field Effect Transistors for Accurate Online Training in Deep Neural Network Accelerators, S Majumdar, I Zeimpekis, Advanced Intelligent Systems, 2300391 (2023).
• Large-area synthesis of high electrical performance MoS2 by a commercially scalable atomic layer deposition process, N Aspiotis, K Morgan, B März, K Müller-Caspary, M Ebert, E Weatherby, S Majumdar, I Zeimpekis, npj 2D Materials and Applications 7 (1), 18 (2023).
• An efficient deep neural network accelerator using controlled ferroelectric domain dynamics, S Majumdar, Neuromorphic Computing and Engineering 2 (4), 041001 (2022).
• Back-End CMOS Compatible and Flexible Ferroelectric Memories for Neuromorphic Computing and Adaptive Sensing, S Majumdar, Advanced Intelligent Systems 4, 2100175 (2022).
• Ultrafast Switching and Linear Conductance Modulation in Ferroelectric Tunnel Junctions via P (VDF-TrFE) Morphology Control, S Majumdar, Nanoscale 13, 11270-11278 (2021).
• Tactile sensory coding and learning with bio-inspired optoelectronic spiking afferent nerves, H Tan, Q Tao, I Pande, S Majumdar, F Liu, Y Zhou, POÅ Persson, J Rosen, S van Dijken, Nature communications 11 (1), 1369 (2020).
• Crossover from synaptic to neuronal functionalities through carrier concentration control in Nb-doped SrTiO3-based organic ferroelectric tunnel junctions, S Majumdar, H Tan, I Pande, S van Dijken, APL Materials 7, 091114 (2019).
• Energy‐Efficient Organic Ferroelectric Tunnel Junction Memristors for Neuromorphic Computing, S Majumdar, H Tan, Q Qin, S van Dijken, Advanced Electronic Materials 5, 1800795 (2019).

• News Links on my Previous research
• News Links on my Previous research published in Times group
• News Links on my Previous research published in EurekaAlert (AAAS)
• News link for ArCTIC project

1. A. Ghosh, A. Spelman, T. H. Cheung, D. Boopathy, K. Stadius, M. D. Gomony, M. Valkama, J. Ryynänen, M. Kosunen, V. Unnikrishnan, "Reconfigurable Signal Processing and DSP Hardware Generator for 5G and Beyond Transmitters," in IEEE Transactions on Very Large Scale Integration (VLSI) Systems, vol. 32, no. 1, pp. 4-15, Jan. 2024, doi: 10.1109/TVLSI.2023.3326159.
2. A. Fischer-Bühner, A. Brihuega, L. Anttila, M. Turunen, V. Unnikrishnan, M. D. Gomony, M. Valkama, "Sparsely Gated Mixture of Experts Neural Network For Linearization of RF Power Amplifiers," in IEEE Transactions on Microwave Theory and Techniques, 2023, doi: 10.1109/TMTT.2023.3341616.
3. V. Lampu, G. Xu, A. Brihuega, M. Kosunen, V. Unnikrishnan, J. Ryynänen, C. Fager, M. Valkama, "Multilevel Outphasing With Over-the-Air Combining in Large Antenna Arrays," in IEEE Transactions on Communications, vol. 71, no. 12, pp. 7347-7362, Dec. 2023, doi: 10.1109/TCOMM.2023.3312683.
4. K. Spoof, M. Tenhunen, V. Unnikrishnan, K. Stadius, M. Kosunen and J. Ryynänen, "True-Time-Delay Receiver IC With Reconfigurable Analog and Digital Beamforming," in IEEE Access, vol. 10, pp. 116375-116383, 2022, doi: 10.1109/ACCESS.2022.3219938.
5. O. Järvinen et al., "Energy-Efficient Cyclic-Coupled Ring Oscillator With Delay-Based Injection Locking," in IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 69, no. 9, pp. 3709-3713, Sept. 2022, doi: 10.1109/TCSII.2022.3176805.
6. O. Järvinen, I. Kempi, V. Unnikrishnan, K. Stadius, M. Kosunen and J. Ryynänen, "Fully Digital On-Chip Wideband Background Calibration for Channel Mismatches in Time-Interleaved Time-Based ADCs," in IEEE Solid-State Circuits Letters, vol. 5, pp. 9-12, 2022, doi: 10.1109/LSSC.2022.3145918.
7. O. Järvinen, V. Unnikrishnan, W. Siddiqui, T. Korhonen, K. Koli, K. Stadius, M. Kosunen, J. Ryynänen, "A 100–750 MS/s 11-Bit Time-to-Digital Converter With Cyclic-Coupled Ring Oscillator," in IEEE Access, vol. 9, pp. 48147-48156, 2021, doi: 10.1109/ACCESS.2021.3068838.
8. V. Unnikrishnan, O. Järvinen, W. Siddiqui, K. Stadius, M. Kosunen and J. Ryynänen, "Data Conversion With Subgate-Delay Time Resolution Using Cyclic-Coupled Ring Oscillators," in IEEE Transactions on Very Large Scale Integration (VLSI) Systems, vol. 29, no. 1, pp. 203-214, Jan. 2021, doi: 10.1109/TVLSI.2020.3031028.
9. K. Spoof, M. Zahra, V. Unnikrishnan, K. Stadius, M. Kosunen and J. Ryynänen, "A 0.6–4.0 GHz RF-Resampling Beamforming Receiver With Frequency-Scaling True-Time-Delays up to Three Carrier Cycles," in IEEE Solid-State Circuits Letters, vol. 3, pp. 234-237, 2020, doi: 10.1109/LSSC.2020.3012654.
10. K. Spoof, V. Unnikrishnan, M. Zahra, K. Stadius, M. Kosunen and J. Ryynänen, "True-Time-Delay Beamforming Receiver With RF Re-Sampling," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 67, no. 12, pp. 4457-4469, Dec. 2020, doi: 10.1109/TCSI.2020.3005475.
11. O. Olabode, M. Kosunen, V. Unnikrishnan, T. Palomäki, T. Laurila; K. Halonen, J. Ryynänen, "Time-Based Sensor Interface for Dopamine Detection," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 67, no. 10, pp. 3284-3296, Oct. 2020, doi: 10.1109/TCSI.2020.3008363.
12. V. Unnikrishnan and M. Vesterbacka, "Mitigation of Sampling Errors in VCO-Based ADCs," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 64, no. 7, pp. 1730-1739, July 2017, doi: 10.1109/TCSI.2017.2670058.
13. V. Unnikrishnan and M. Vesterbacka, "Time-Mode Analog-to-Digital Conversion Using Standard Cells," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 61, no. 12, pp. 3348-3357, Dec. 2014, doi: 10.1109/TCSI.2014.2340551.

Full list here. 

1. Amit Tewari, Srinivas Gandla, Anil Reddy Pininti, K Karuppasamy, Siva Böhm, Arup R Bhattacharyya, Christopher R McNeill, Dipti Gupta, “High-mobility and low-operating voltage organic thin film transistor with epoxy-based siloxane binder as the gate dielectric”. Applied Physics Letter, 103302 (1-4), 107 (2015)

2. Amit Tewari, Siva Bohm, Srinivas Gandla, Christopher R McNeill, Dipti Gupta, “Graphene-MWNTs composite coatings with enhanced electrical conductivity”. FlatChem, 33- 41, 4, 2017

3. Amit Tewari, Srinivas Gandla, Siva Bohm, Christopher R. McNeill, Dipti Gupta “Highly exfoliated MWNT-rGOA ink wrapped Polyurethane foam for Piezoresistive pressure sensor applications” ACS Appl. Mater. Interfaces, 5185–5195, 10, 2018

4. Amit Tewari, Srinivas Gandla, Siva Bohm, Christopher R. McNeill, Dipti Gupta, “Rapid Dip-Dry MWNT-rGO Ink Wrapped Polyester Elastic Band (PEB) For Piezoresistive Strain Sensor Applications” Applied Physics Letter, 084101 (1–5), 113 (2018)

5. Amit Tewari, Srinivas Gandla, Siva Bohm, Christopher R. McNeill, Dipti Gupta, “Remarkable Wettability of Highly Dispersive rGO Ink on Multiple Substrates Independent of Deposition Techniques”. FlatChem, 100-110, 16, 2019

6. Jae-seok Yoon*, Amit Tewari*, Changhwan Shin, Senior Member IEEE, Sanghun Jeon, Senior Member IEEE, “Influence of High Pressure Annealing on Memory Properties of Hf0.5Zr0.5O2 Based 1T-FeRAM”. IEEE Electron Device Letters, 1076-1079, 40 (2019).  (J.Y. and A.T. contributed equally to this work)

7. Amit Tewari, Hugo Huerta, Gary Chinga Carrasco, Samuli Ranta, Ronald Österbacka, Martti Toivakka, “Low-Cost Biodegrable Dielectric Sheets for Large-Area Floor Sensing Applications”. Flexible and Printed Electronics, 7 (2022) 045005

8. Amit Tewari, Kim Björkström, Amir Mohammad Ghafari, Eleonora Macchia, Luisa Torsi, Ronald Österbacka, “Stability of thiol-based self-assembled monolayer functionalized electrodes in EG-OFET-based applications”. FlatChem, 42 (2023) 100553

9. Eleonora Macchia*, Kim Björkström*, Amit Tewari*, Ville Eskonen, Axel Luukkonen, Amir Mohammad Ghafari, Lucia Sarcina, Mariapia Caputo, Natalia Tong-Ochoa, Kari Kopra, Fredrik Pettersson, Zahra Gounani, Luisa Torsi, Harri Härmä, Ronald Österbacka, “Label-free electronic detection of peptide post-translational modification with functional enzyme-driven assay at the physical limit”. Cell Reports Physical Science 5, 101874, 2024. (EM, KB, and AT contributed equally to this work)

10. Amit Tewari*, Antti TukiainenMatti Mäntysalo, Paul R. Berger, “Direct PEALD Deposition of a HfO2 Gate Dielectric without the Passivation for TFTs on Rigid and Flexible Substrates”. ACS Applied Electronics Materials, 7, 7120−7130, 2025

• News Link to my Past Research
• News Link to my Past Research