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Complex systems

Using an electronic and electrochemical platform with many nonlinearly interacting sub systems that are thoroughly open to the external world, we are investigating how to realize complex systems that can manifest collaborative behaviors, leading to emergent collective behaviors with autonomy, adaptivity, self-organization, and memory at the edge of chaos.

Integrated circuits

We design a broad gamut of RF/microwave, analog, mixed-signal, and digital integrated circuits in silicon (CMOS) technology as well as with III-V semiconductor technology, organic materials, and emerging nanoscale materials such as semiconductor nanowires. Our design portfolio includes a host of frequency reference circuits—e.g., self-sustained ring, LC, and wave oscillators, mode-locked (soliton) oscillators, integer/fractional-N phase-locked loop (PLL) frequency synthesizers, and delay-locked-loop (DLL) timing references—, time-domain temperature sensors for microprocessor thermal profiling, analog-to-digital converters (ADCs) with various digital background calibration techniques, and a variety of application-specific integrated circuits—e.g.micro electromagnet circuits to manipulate biological cells, RF NMR relaxometry chips to detect cancer marker proteins and human cancer cells and to analyze complex hydrocarbons for petrochemical analysis, RF NMR spectrometer chips to interrogate atomic networks of complex molecules, CMOS ion-sensitive field effect transistor (ISFET) array for all-electrical DNA array technology, and a CMOS chip that operates an interface between a neuronal network and an array of vertical conducting nanowires.

Facilities

DONHEE HAM LAB FACILITIES

Our laboratory, located in Maxwell Dworkin Laboratory, is equipped with facilities for radio-frequency and microwave measurements, THz spectroscopy with femtosecond laser, and optical spectroscopy for experimentation with various solid-state devices and circuits at room as well as cryogenic temperatures, and facilities for cell biology, electrophysiology, electrochemistry, and fluorescence imaging. Specifically:

(1) Cascade Microtech RF/microwave (~110 GHz) probe station with an Nd:Yag laser for metal trimming and a micro chamber for EMI shielding;
(2) Lakeshore cryogenic (~ 1.5 Kelvin) RF/microwave (~67 GHz) probe station;
(3) Nikon LV 150 reflected light microscope;
(4) Oxford Instrument 3T superconducting magnet;
(3) Ti:sapphire femtosecond laser;
(4) Time-domain THz spectroscopy system (0.3~10 THz);
(5) Agilent spectrum analyzers with a built-in phase noise measurement capability (50 GHz);
(6) Two Agilent vector network analyzers (50 GHz, 9 GHz);
(7) Agilent CW signal generators (50 GHz);
(8) Agilent digital communication analyzer (80 GHz electrical, 40 GHz optical);
(9) Agilent real-time oscilloscope (6 GHz; 20 Gs/sec);
(10) HP real-time oscilloscope (500 MHz; 1 Gs/sec);
(11) Tektronix real-time oscilloscope (200 MHz, 2 Gs/s);
(12) Agilent function generator (120 MHz);
(13) Agilent logic analyzer;
(14) Two Stanford Research lock-in amplifiers;
(15) Agilent high-precision power supply;
(16) AES temperature chamber (-65°C~200°C);
(17) Westbond wire bonder; chip assembly & packaging facilities;
(18) Chemical vapor deposition setup for graphene and carbon nanotube growth;
(19) Semiconductor integrated circuits design EDA (Cadence, ADS, and Hspice);
(20) Electromagnetic Field solvers (HFSS, Sonnet, Maxwell);
(21) Cell culture and biology facilities;
(22) Electrophysiology capabilities;
(23) Electrochemistry capabilities;
(24) High-end microwave cables, adapters, connectors, on-chip probes, and numerous general purpose power supplies and multimeters.


HARVARD CENTER FOR NANOSCALE SYSTEMS SHARED FACILITIES

Harvard University's CNS houses, in 85,000-ft2 Laboratory for Integrated Science and Engineering (LISE), shared nano fabrication and characterization facilities, maintained by technical staff supported by Harvard. This is a major investment by Harvard to promote interdisciplinary research on small structures in areas including Electrical Engineering, Applied Physics, Biology, and Chemistry. CNS facilities include: 1) clean rooms for soft lithography and for optical & e-beam lithography equipped with e-beam lithography systems. Clean room facilities also include etching, deposition, and other aspects of nanofabrication, 2) imaging laboratory that includes SEMs, STEM, & TEM, and 3) advanced materials synthesis and processing equipment.

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