Ongoing Projects
Ongoing Projects
Self-Amplified Silicon-Germanium Nanomechanical Resonator With Piezoresistive Heat Engines (UMich)
Summary: My research at the University of Michigan focuses on investigating thermomechanical phenomena in silicon-silicon-germanium (Si-SiGe) acoustic resonators to advance the understanding and control of temperature-dependent mechanical behavior. This work involves designing and fabricating high-quality-factor resonators that utilize advanced architectures, such as SiGe/n-Si superlattices with integrated piezoresistive heat engines, to enable self-amplification and tailored nonlinear dynamics.
Completed Projects
Ultimately Scaled Trampoline Optomechanical Resonator Pixels and Arrays for Ultrasensitive Infrared Detection
Funding: Defense Advanced Research Projects Agency (DARPA) DSO, USA
Award Name: OpTIm (Optomechanical Thermal Imaging) - Phase I
Web Link: https://www.darpa.mil/research/programs/optomechanical-thermal-imaging
Summary: We have designed and experimentally demonstrated highly miniaturized and ultrathin (toward the ultimate limits) optomechanical graphene trampoline resonators (in both single pixels and towards scalable arrays) for ultrasensitive infrared (IR) detection in uncooled, room-temperature conditions. The operating principles and engineering designs of these optomechanical resonant IR sensors are based upon the IR-thermal-optomechanical transduction, from which we have developed a self-contained model. This allows us to quantitatively investigate the multiphysics effects and multi-parameter spaces, and to engineer the tradeoffs. The devices have lateral sizes on the order of ~10μm, thus well ensuring a single-pixel effective area <(100μm)2 (104μm2). Operating at room temperature without cooling, the vibrating optomechanical pixels behave as highly elastic trampolines. These new devices can achieve the IR detection at the fundamental limits via (1) exceptionally-high frequency-shift responses to IR photons by exploiting ultrahigh membrane size-to-thickness ratios of atomically thin resonators, (2) reaching high IR absorption via 2D-material metasurface absorbers with absorption band control and spectral tunability, (3) attaining the quantum (shot) noise limited displacement sensing via photonic and phononic band engineering, (4) spectrally resolving IR radiation using multimode mechanical resonances.
Applications: Infrared (IR) detectors underpin a vast application space including night vision, battlefield surveillance, terrestrial and space imaging, biochemical fingerprinting, and non-invasive medical diagnosis.
Publications: (a) Pending patent (PROV Appl. No. 63/818,295, filed June 5, 2025). (b) “Graphene Trampoline Nanomechanical Resonators with Very High Quality Factors and Broad Dynamic Ranges”, Advanced Functional Materials, vol. 35, no. 48, art. no. e11158 (2025).
Phononic Frequency Combs in Atomically Thin MoS2 NEMS Resonators (UF)
Funding: National Science Foundation (NSF) QuSeC-TAQS program (Grant OSI-2326528), CAREER (Grant ECCS-2015708), Collaborative Research (Grant CCF-2103091)
Web Link: NSF Award Search: Award # 2326528, NSF Award Search: Award # 2015708, NSF Award Search: Award # 2103091
Summary: Frequency comb refers to the comb-like spectrum composed of discrete and equidistant frequency spikes, individually referred to as “comb teeth”. We have experimentally demonstrated phononic frequency comb (PnFC) (analogue of optical frequency combs in radiofrequency domain) generation from a drumhead resonator made from a bilayer MoS2 flake. Driving the device with a large RF drive voltage (>300mV) into the deep nonlinear regime produces mode coupling leading to PnFC.
Applications: Precision navigation for warfighters via a handheld device in GPS-denied environments, Inertial sensors and gyroscope, Infrared detection, sensitive multispecies highly complex trace-gas sensing.
Publications: (a) “Phononic Frequency Combs in Atomically Thin Nanoelectromechanical Resonators via 1:1 and 2:1 Internal Resonances”, Journal of Microelectromechanical Systems, vol. 32, no. 4, pp. 335-346 (2023). (b) “Nonlinear Coupling of Closely Spaced Modes in Atomically Thin MoS2 Nanoelectromechanical Resonators”, Microsystems and Nanoengineering, vol. 10, art. no. 206 (2024).
Mechanical Resonant Sensing of Spin Texture Dynamics in 2D Antiferromagnet
Funding: National Science Foundation (NSF) QuSeC-TAQS Program (Grant OSI-2326528), USA and Department of Energy (DOE) (Grant DE-SC002298)
Award Name: Driving advances in magnetic materials & devices with quantum sensing of magnons; Optical manipulation of magnetic order in van der Waals heterostructures
Web Link: NSF Award Search: Award # 2326528 and Public Abstract
Summary: We report the detection of collective spin texture dynamics with nanoelectromechanical resonators made of two-dimensional antiferromagnetic (AFM) MnPS3. By examining their radio frequency mechanical oscillations under magnetic fields, new magnetic transitions were identified with sharp dips in resonant frequency. They are attributed to the collective AFM domain wall motions as supported by the analytical modeling of magnetostriction effects and large-scale spin-dynamics simulations. Additionally, an abnormally large modulation in the mechanical nonlinearity at the transition field infers a fluid-like response due to the ultrafast domain motion. Our work establishes a strong coupling between spin texture dynamics and mechanical vibrations, which lays the foundation for electromechanical manipulation of spin texture and developing quantum hybrid devices.
Applications: The findings will inspire the next generation nanomechanical devices coupled to spin textures for both classical and quantum information technologies, memory technologies, and energy efficient devices for power hungry artificial intelligence (AI).
Collaboration: This project is in collaboration with the National High Magnetic Field Laboratory at Tallahassee, Department of Physics at the University of Florida, Institute for Condensed Matter Physics and Complex Systems at the University of Edinburgh (UK), Donostia International Physics Center (Spain), and Higgs Centre for Theoretical Physics at the University of Edinburgh (UK).
Publications: (a) “Mechanical Resonant Sensing of Spin Texture Dynamics in a 2D Antiferromagnet”, Advanced Materials, vol. 37, art. no. 2420168 (2025). [Featured as inside back cover] (b) “Two-Dimensional FePS3 Nanoelectromechanical Resonators with Local-Gate Electrostatic Tuning at Room Temperature”, Journal of Applied Physics, vol. 136, art. no. 23 (2024).
Vibrating Channel Transistors (VCTs)
Funding: National Science Foundation (NSF) ECCS EAGER Program (Grant No. ECCS-2221881)
Web Link: NSF Award Search: Award # 2221881
Summary: Fundamental scaling principle for electronic devices, known as Moore’s law, predicts that the number of transistors on a chip doubles approximately every two years. To enable greater computational power on a chip, the industry is advancing toward three-dimensional (3D) device stacking, an approach referred to as “More Moore.” “More than Moore” involves the integration of non-computational functionalities using novel and emerging materials through heterogeneous integration with 3D chips. In this work, we have investigated vibrating channel transistors using single and few-layer MoS2 flakes. Vibrating channel transistors are unique devices that combine the mechanical and electrical degrees of freedom of the nanoscale devices and enable direct electrical readout of the mechanical motion of the suspended membrane.
Applications: Development of ultrasensitive on-chip displacement sensors for precision navigation for warfighters, next generation transistors, and harsh environment sensing.
Publications: (a) “Atomic Layer Self-Transducing MoS2 Vibrating Channel Transistors with 0.5 pm/Hz1/2 Displacement Sensitivity at Room Temperature”, Applied Physics Letters, vol. 124, art. no. 053503 (2024). (b) “High-Performance Monolayer and Bilayer MoS2 Vibrating Channel Transistors for Ultrasensitive Drain-Source Current Readout of Resonant Motion”, in Proc. 2023 International Electron Devices Meeting (IEDM 2023), Dec. 2023, pp. 17.4.1-17.4.4.
Raman Spectroscopic Probe for Nanoelectromechanical Resonators
Funding: National Science Foundation (NSF) CAREER Award (Grants ECCS-1454570, ECCS-2015708) and EPMD Program (Grant ECCS 2015670)
Web Link: NSF Award Search: Award # 1454570, NSF Award Search: Award # 2015708, NSF Award Search: Award # 2015670
Summary: We demonstrate a hybrid spectromechanical platform that couples Raman spectroscopy with optical interferometry to probe vibrational dynamics in atomically thin MoS₂ nanoelectromechanical resonators (NEMS). By driving monolayer to trilayer MoS2 resonators into nonlinear resonance, we reveal phonon softening and enhanced Raman signal intensity-directly linking nanoscale mechanical motion to atomic lattice vibrations. This work establishes Raman spectroscopy as a powerful probe of dynamic strain and multiphysics interactions in 2D NEMS.
Applications: Raman spectroscopy is a powerful, non-invasive technique for probing the atomic-scale properties of 2D materials. It enables the development of ultra-sensitive sensors, flexible electronics, and quantum devices- advancing technologies critical to U.S. leadership in national security, healthcare, and clean energy.
Publications: (a) “Raman Spectroscopic Probe for Nonlinear MoS2 Nanoelectromechanical Resonators”, Nano Letters, vol. 22, no. 14, pp. 5780-5787 (2022). (b) “Silicon Phononic Nanowires Enable Ultra-Low Thermal Conductivity Measured by Raman Spectroscopy”, IEEE Photonics Technology Letters, vol. 36, no. 5, pp. 325-328 (2024).
Plasmonic Nanostructures and Devices
Undergraduate Thesis: Lumerical FDTD simulation to evaluate plasmonic devices for various sensing applications, such as virus detection and temperature sensing.
Publications: (a) “A High-Performance Plasmonic Nanosensor Based on an Elliptical Nanorod in an MIM Configuration”, IEEE Sensors Journal, vol. 18, no. 15, pp. 6145-6153 (2018). (b) “Proposition and Numerical Analysis of a Plasmonic Sensing Structure of Metallo-Dielectric Grating and Silver Nano-Slabs in a Metal-Insulator-Metal Configuration”, Plasmonics, vol. 13, pp. 2205-2213 (2018).
Synthesis and Characterization of Multiferroic Nanoparticles for Energy Applications
Funding: Ministry of Science and Technology, Government of Bangladesh, Grant No.: 39.009.002.01.00.053.2014-2015/PHYS-273/ (26.01.2015); The World Academy of Sciences (TWAS), Ref.:14-066 RG/PHYS/AS-I; UNESCO FR: 324028567; Infrastructure Development Company Limited (IDCOL), Dhaka, Bangladesh; and the Ministry of Education, Government of Bangladesh (Grant No. PS 14267).
Summary: Recently, there has been a great interest for the study of the multiferroic materials, in which ferromagnetic, ferroelectric, and/or ferroelastic orderings coexist. The co-existence of “ferro”-orders in multiferroics opens pathways for the possibility that the magnetization can be controlled by the electric field and vice versa. The ability to manipulate the magnetic and ferroelectric properties of multiferroic BiFeO3 (BFO) by dopants opens promising opportunities for fabricating new multiferroic materials in the field of information storage technology.
Applications: Multiferroic materials enable ultra-low power memory, spintronic devices, and tunable microwave components essential for advanced computing, secure communications, and defense systems. Their use in quantum technologies, energy harvesting, and high-sensitivity sensors supports critical national interests in security, infrastructure, and technological leadership.
Publications: (a) “Temperature-Dependent Phase Transition and Comparative Investigation on Enhanced Magnetic and Optical Properties Between Sillenite and Perovskite Bismuth Ferrite-rGO Nanocomposites”, J. Appl. Phys., vol. 122, no. 18, Art. no. 084902 (2017). (b) “The 10% Gd and Ti Co-Doped BiFeO3: A Promising Multiferroic Material”, J. Alloys Compd., vol. 694, pp. 792-799 (2017).