Professor, Electrical and Computer Engineering
| ali.gokirmak@uconn.edu | |
| Phone | (860) 486-9425 |
| Mailing Address | Electrical and Computer Engineering 371 Fairfield Way U-4157 Storrs, Connecticut 06269-4157 |
| Campus | Storrs |
| Link | Department Page |
| Google Scholar Link | |
Brief Bio
- Phase change memory (PCM)
- Thermoelectric effects
- Phase change logic
- Current induced crystallization
- Applications of nanostructures
- Nanofabrication technologies
- Small-scale MOSFET’s for sensors, logic and non-volatile memories
- Electrical characterization
- Finite element modeling
- Phase Change Memory
- Multi-contact Phase Change logic devices
- Thermoelectric transport under large temperature gradients
- Silicon crystallization by self-heating for large area electronics
- Multi-gate silicon transistors for low power applications
- Light emission from zinc oxide nanorods
- Solid-liquid phase change oscillators
- Instrument development
ECE 2001 – Electrical Circuits (A. Gokirmak): offered in Spring
Analysis of electrical networks incorporating passive and active elements. Basic laws and techniques of analysis. Transient and forced response of linear circuits. AC steady state power and three-phase circuits. Periodic excitation and frequency of response. Computer analysis tools. Design projects are implemented and tested in the laboratory. Laboratory reports with revisions are required for each project.
ECE 3001 – Electromagnetic Fields and Waves (H. Silva): offered in Spring
ECE 3001 is a comprehensive undergraduate course on electromagnetic fields and waves for electrical engineers. It focuses on application of electric and magnetic field theory to engineering problems involving conductors, dielectrics, semiconductors, magnetic materials, the motion of charged particles, and wave propagation.
ECE 3245/ENGR 3195 – Introduction to Nanotechnology / Nanoscience and Society (H. Silva)
Basic concepts of nanoscience; new physical properties at these scales (~1-100 nm); different approaches to fabricate, image, characterize and manipulate nanostructures and nanodevices; current and potential applications in areas as diverse as electronics, health and energy; societal impacts of nanotechnology.
ECE 4225/5225 – Electronic Device Design and Characterization (A. Gokirmak): offered in Fall
Design of micro/nano electronic devices using state-of-art computer simulation tools, experimental electrical characterization of semiconductor devices and introduction to modern electronic devices such as high-performance MOSFETs, TFTs, solar cells, non-volatile memories, CCDs, and thermoelectric power generators.
ECE 4095/6095 – Memory devices and technologies (H. Silva): offered in Spring
A survey of current semiconductor memory (flash, DRAM, SRAM) and alternative memory technologies (MRAM, FeRAM, RRAM, Phase-change memory).
- R. Khan, A. H. Talukder, F. Dirisaglik, H. Silva, A. Gokirmak, Accelerating and Stopping Resistance Drift in Phase Change Memory Cells via High Electric Field Stress, arXiv preprint arXiv:2002.12487
- J. Scoggin, H. Silva, A. Gokirmak, Field Dependent Conductivity and Threshold Switching in Amorphous Chalcogenides–Modeling and Simulations of Ovonic Threshold Switches and Phase Change Memory Devices, arXiv preprint arXiv:1906.09316, under revision
- N. Noor, S. Muneer, R. Khan, A. Gorbenko, H. Silva, Amorphized Length and Variability in Phase Change Memory Line Cells, www.beilstein-archives.org/xiv/preprints/202058, under review.
- R. Khan, F. Dirisaglik, A. Gokirmak, H. Silva, Resistance drift in Ge2Sb2Te5 phase change memory line cells at low temperatures and its response to photoexcitation, Applied Physics Letters. 116 (25), 253501 (2020).
- A. Cywar, Z. Woods, S. Kim, M. BrightSky, N. Sosa, Y. Zhu, H. S. Kim, H. K. Kim, C. Lam, A. Gokirmak, H. Silva, Modeling of void formation in phase change memory devices, Solid-State Electronics, 164, 107684 (2020).
- S. Tripathi, P. Kotula, M. Singh, C. Ghosh, G. Bakan, H. Silva, C. B. Carter, C Barry, Role of oxygen on chemical segregation in uncapped Ge2Sb2Te5 thin films on silicon nitride, ECS Journal of Solid State Science and Technology, in press https://doi.org/10.1149/2162- 8777/ab9a19 (2020).
- J. Scoggin, Z. Woods, H. Silva, A. Gokirmak, Modeling heterogeneous melting in phase change memory devices, Applied Physics Letters 114, 043502 (2019).
- S. Muneer, J. Scoggin, F. Dirisaglik, L. Adnane, A. Cywar, G. Bakan, K. Cil, C. Lam, H. Silva, and A. Gokirmak. “Activation energy of metastable amorphous Ge2Sb2Te5 from room temperature to melt” AIP Advances 8, no. 6, 065314 (2018).
- J. Scoggin, R. Khan, H. Silva, and A. Gokirmak. “Modeling and impacts of the latent heat of phase change and specific heat for phase change materials.” Applied Physics Letters 112, no. 19, 193502 (2018).
- M. Akbulut , F. Dirisaglik, A. Cywar, A. Faraclas, D. Pence, J. Patel, S. Steen, R. Nunes, H. Silva, and A. Gokirmak, “Nanoscale Accumulated Body Si nMOSFETs,” IEEE Trans. Electron Devices 65, no. 4, 1283-1289 (2018).
- L. Adnane, F. Dirisaglik, A. Cywar, K. Cil, Y. Zhu, C. Lam, A. F. M. Anwar, A. Gokirmak, and H. Silva, “High temperature electrical resistivity and Seebeck coefficient of Ge2Sb2Te5 thin films,” J. Appl. Phys. 122, 125104 (2017).
- Z. Woods, J. Scoggin, A. Cywar, L. Adnane, and A. Gokirmak, “Modeling of Phase-Change Memory: Nucleation, Growth, and Amorphization Dynamics During Set and Reset: Part II–Discrete Grains,” IEEE Trans. Electron Devices 64, no. 11, 4472-4478 (2017).
- Z. Woods and A. Gokirmak, “Modeling of Phase-Change Memory: Nucleation, Growth, and Amorphization Dynamics During Set and Reset: Part I–Effective Media Approximation,” IEEE Trans. Electron Devices 64, no. 11, 4466-4471 (2017).
- A. Deschenes, S. Muneer, M. Akbulut, A. Gokirmak and H. Silva, “Analysis of self-heating of thermally assisted spin-transfer torque magnetic random access memory,” Beilstein Journal of Nanotechnoly 7, 1676–1683 (2016).
- G. Bakan, B. Gerislioglu,F. Dirisaglik, Z. Jurado, L. Sullivian, A. Dana, C. Lam, A. Gokirmak, H. Silva, “Extracting the temperature distribution on a phase-change memory cell during crystallization,” J. Appl. Phys. 120, 164504 (2016).
- L. Adnane, A. Gokirmak and H. Silva, “High temperature Hall measurement setup for thin film characterization,” Rev. Sci. Instrum. 87, 075117 (2016).
- N. Kan’an, H. Silva and A. Gokirmak, “Phase-change pipe for non-volatile routing,” Journal of the Electron Devices Society 4, no. 2, 72-75 (2016).
- F. Dirisaglik, G. Bakan, Z. Jurado, S. Muneer, M. Akbulut, J. Rarey, L. Sullivan, M. Wennberg, A. King, L. Zhang, R. Nowak, C. Lam, H. Silva and A. Gokirmak, “High speed, high temperature electrical characterization of phase change materials: metastable phases, crystallization dynamics, and resistance drift,” Nanoscale 7, 16625-16630 (2015).
- N. Noor, L. Lucera, T. Capuano, V. Manthina, A. G. Agrios, H. Silva and A. Gokirmak, “Blue and white light emission from zinc oxide nanoforests,” Beilstein J. Nanotechnol 6, 2463–2469 (2015).
- L. Adnane, N. Williams, H. Silva and A. Gokirmak, “High temperature setup for measurements of Seebeck coefficient and electrical resistivity of thin films using inductive heating,” Review of Scientific Instruments 86, 105119 (2015).
- N. Noor, V. Manthina, K. Cil, L. Adnane, A. G. Agrios, A. Gokirmak, H. Silva, “Atmospheric pressure microplasmas in ZnO nanoforests under high voltage stress,” AIP Advances 5, 097212 (2015).
- M.B. Akbulut, H. Silva, and A. Gokirmak, “Three-Dimensional Computational Analysis of Accumulated Body MOSFETs.pdf,” IEEE Transactions on Nanotechnology, vol.14, no.5, pp.847-853, Sept. 2015, 10.1109/TNANO.2015.2451153 (PDF Copy.pdf)
S.Muneer, A.Gokirmak, H. Silva, “Vacuum-Insulated Self-Aligned Nanowire Phase-Change Memory Devices,” IEEE Trans. on Electron Devices 62, 5, 1668-1671 (2015). 10.1109/TED.2015.2414716
G. Bakan, A. Gokirmak, H. Silva, “Suppression of thermoelectric Thomson effect in silicon microwires under large electrical bias and implications for phase-change memory devices,” Journal of Applied Physics 116, 23, 234507 (2014) http://dx.doi.org/10.1063/1.4904746
F. Dirisaglik, G. Bakan, A. Faraclas, A. Gokirmak, H. Silva, “Numerical Modeling of Thermoelectric Thomson Effect in Phase Change Memory Bridge Structures,” Inter. J. High Speed Electr. and Sys., 23, 2 (2014) DOI: 10.1142/S0129156414500049
M. Staruch, K. Cil, H. Silva, J. Xiong, Q.X. Jia, and M. Jain, “Effect of Mn Doping on the Properties of Sol-gel Derived Pb0.3Sr0.7TiO3 Thin Films,” Ferroelectrics 470:227–233, (2014) DOI: 10.1080/00150193.2014.923684
A. Faraclas, G. Bakan, L. Adnane, F. Dirisaglik, N. Williams, A. Gokirmak and H. Silva, “Modeling of thermoelectric effects in phase change memory cells,” IEEE Trans. on Electron Devices, 61, 2, 372-387, 10.1109/TED.2013.2296305 (2014).
M. Trombetta, N. Williams, S. Fischer, A. Gokirmak, H. Silva, “Finite element electrothermal modeling of nanocrystalline phase-change materials using a mesh-based crystallinity approach,” Electronic Letters 50, 2, pp. 100-101, DOI: 10.1049/el.2013.2253 (2014).
G. Bakan, N. Khan, H. Silva, A. Gokirmak, “High-temperature thermoelectric transport at small scales: generation, transport and recombination of minority carriers,” Scientific Reports 3, 2724, doi: 10.1038/srep02724 (2013).
N. Kan’an, A. Faraclas, N. Williams, H. Silva and A. Gokirmak, “Computational Analysis of Rupture Oxide Phase Change Memory Cells”, IEEE Trans. on Electron Devices 60, 5, 1649 – 1655 (2013) 10.1109/TED.2013.2255130.
S. Fischer, C. Osorio, S. Ayas, N. Williams, H. Silva, A. Gokirmak, “Percolation transport and filament formation in nanocrystalline silicon nanowires,” Journal of Applied Physics, 113, 164902 (2013) http://jap.aip.org/resource/1/japiau/v113/i16/p164902_s1
K. Cil, Y. Zhu, J. Li, C. H. Lam, H. Silva*, “Assisted cubic to hexagonal phase transition in GeSbTe thin films on silicon nitride,” Thin Solid Films, available online April 2013; http://dx.doi.org/10.1016/j.tsf.2013.03.087.
K. Cil, F. Dirisaglik, M. Wennberg, A. King, A. Faraclas, M. Akbulut, Y. Zhu, C. Lam, A. Gokirmak, H. Silva*, “Electrical resistivity of liquid Ge2Sb2Te5 nanostructures,” IEEE Trans. on Electron Devices 60, 1, 433-437 (2013); 10.1109/TED.2012.2228273.
G. Bakan, L. Adnane, A. Gokirmak, H. Silva, “Extraction of temperature dependent electrical resistivity and thermal conductivity from silicon microwires self-heated to melting temperature,”J. Appl. Phys. 112, 063527 (2012); http://dx.doi.org/10.1063/1.4754795. Pdf copy.pdf (Copyright 2012 American Institute of Physics)
- N. Williams, H. Silva, A. Gokirmak, “Finite Element Analysis of Scaling of Silicon Micro-thermoelectric generators to nanowire dimensions,” J. Renewable Sustainable Energy 4, 043110 (2012) http://dx.doi.org/10.1063/1.4738592
- N. Williams, H. Silva, A. Gokirmak, “Nanoscale RingFETs,” IEEE Electron Device Letters 33, 10, 1339 – 1341 (2012) 10.1109/LED.2012.2208093
- A. Cywar, H. Silva, A. Gokirmak, “Finite Element Modeling of a Nanowire-Based Oscillator Achieved Through Solid-Liquid Phase Switching for GHz Operation”, Solid State Electronics 78, 97-101 (2012) http://dx.doi.org/10.1016/j.sse.2012.05.067
- A. Cywar, J. Li, C. Lam, H. Silva, “The impact of heater-recess and load matching in phase change memory mushroom cells,” Nanotechnology 23, 22, 225201(2012).
- H. Silva, G. Bakan, A. Cywar, N. Williams, N. Henry, F. Dirisaglik, A. Gokirmak, “Crystallization of silicon microstructures through rapid self-heating for high-performance electronics on arbitrary substrates,” Nanoscience and Nanotechnology Letters 4, 10, 970-976 (2012) http://dx.doi.org/10.1166/nnl.2012.1438
- M. Staruch, K. Cil, H. Silva, J. Xiong, Q.X. Jia, and M. Jain, “Effect of Mn Doping on the Properties of Sol-gel Derived Pb0.3Sr0.7TiO3 Thin Films,” Integrated Ferroelectrics (special issue, in press, 2012).
- H.K. Peng, K. Cil, A. Gokirmak, G. Bakan, Y. Zhu, C.S. Lai, C.H. Lam, H. Silva, “Thickness dependence of the amorphous-cubic and cubic-hexagonal phase transition temperatures of GeSbTe thin films on silicon nitride,” Thin Solid Films, vol. 520, pp. 2976-2978, 2011.
- A. Faraclas, N. Williams, A. Gokirmak, H. Silva, “Modeling of Set and Reset Operations of Phase-Change Memory Cells,” Electron Device Letters, IEEE, 32, 12, 1737 – 1739 (2011).
- A. Cywar, F. Dirisaglik, M. Akbulut, G. Bakan, S. Steen, H. Silva, A. Gokirmak, “Scaling of Silicon Phase-Change Oscillators,” Electron Device Letters, IEEE, vol. 32, pp. 1486-1488, 2011.
- G. Bakan, N. Khan, A. Cywar, K. Cil, M. Akbulut, A. Gokirmak, H. Silva, “Self-heating of silicon microwires: Crystallization and thermoelectric effects,” Journal of Material Research, vol. 26, Issue 9, pp. 1061-1071, 2011. Invited Feature Paper. Pdf copy.pdf (Copyright 2011 Cambridge University Press and Materials Research Society )
- A. Cywar, G. Bakan, H. Silva and A. Gokirmak, “Nanosecond Pulse Generation in a Silicon Microwire,” Electron Device Letters, IEEE, vol. 31, pp. 1362-1364, 2010.
- W. Jia, Y. Wang, J. Basu, T. Strout, C. B. Carter, A. Gokirmak and Y. Lei, “Nanoengineered Transparent, Free-Standing, Conductive Nanofibrous Membranes,” J. Phys. Chem. C, vol. 113, pp. 19525-19530, 2009.
- A. Gokirmak, H. Inaltekin and S. Tiwari, “Attofarad resolution capacitance–voltage measurement of nanometer scale field effect transistors utilizing ambient noise,” Nanotechnology, vol. 20, pp. 335203, 2009.
- G. Bakan, A. Cywar, H. Silva and A. Gokirmak, “Melting and crystallization of nanocrystalline silicon microwires through rapid self-heating,” Appl. Phys. Lett., vol. 94, pp. 251910, 2009. Pdf copy.pdf (Copyright 2009 American Institute of Physics)
- A. Cywar, G. Bakan, C. Boztug, H. Silva and A. Gokirmak, “Phase-change oscillations in silicon microwires,” Appl. Phys. Lett., vol. 94, pp. 072111, 2009. Pdf copy.pdf (Copyright 2009 American Institute of Physics)
- K. M. Fan, C. S. Lai, H. Silva, C. F. Ai and C. R. Chen, “Programming Speed Enhancement by NH Plasma Nitridation of Tunneling Oxide for Ge Nanocrystals Memory,” J. Electrochem. Soc., vol. 155, pp. H889 – H894, (2008).
- K. J. Lee, R. LaComb, B. Britton, M. Shokooh-Saremi, H. Silva, E. Donkor, Y. Ding and R. Magnusson, “Silicon-Layer Guided-Mode Resonance Polarizer With 40-nm Bandwidth,” IEEE Photonics Technology Letters, vol. 20, 1857-1859 (2008).
- A. Gokirmak and S. Tiwari, “Accumulated body ultranarrow channel silicon transistor with extreme threshold voltage tunability,” Appl. Phys. Lett., vol. 91, pp. 243504, 2007. Pdf copy.pdf (Copyright 2007 American Institute of Physics)
- H. Silva and S. Tiwari, “Random telegraph signal in nanoscale back-side charge trapping memories,” Appl. Phys. Lett., vol. 88, pp. 102105, 2006. Pdf copy.pdf (Copyright 2006 American Institute of Physics)
- A. Gokirmak and S. Tiwari, “Threshold voltage tuning and suppression of edge effects in narrow channel MOSFETs using surrounding buried side-gate,” Electron. Lett., vol. 41, pp. 157-158, 2005.
- H. Silva and S. Tiwari, “A nanoscale memory and transistor using backside trapping,” Nanotechnology, IEEE Transactions on, vol. 3, pp. 264-269, 2004.
- H. Silva, M. K. Kim, U. Avci, A. Kumar and S. Tiwari, “Nonvolatile Silicon Memory at the Nanoscale,” MRS Bull, pp. 845, 2004.