Biomolecular analysis with nanopores
We are applying the unique capabilities of our recently developed sub-nanometer precision transmission electron beam ablation lithography (TEBAL) to demonstrate that the precise integration of solid-state nanopores with nanoelectrodes, nanochannels and microfluidics will address key obstacles that must be overcome to achieve nanopore-based low-cost high-speed single molecule analysis of DNA and proteins.
Graphene, a two-dimensional carbon crystal, has been the focus of intense research since techniques were developed to extract it from graphite in the form of multi-layers and single layers. Graphene-based devices measured on substrates have revealed an impressive set of exotic electronic and optical properties with promising applications.We have recently investigated the possibility of cutting graphene sheets with electron beams and further sculpting them into arbitrary designs that may prove useful in graphene-based electronic and mechanical applications.
We study biomolecule (DNA) translocations through nanopores created in graphene membranes. Devices consist of thin graphene membranes with electron-beam sculpted nanoporesa few nanometers in diameter. Due to the thin nature of the graphene membranes, larger blocked currents are measured than for traditional solid-state nanopores. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control is performed directly at the pore.
Nanoparticle synthesis, assembly and manipulation
We prepare semiconductor nanoparticles of different sizes and shapes using organometallic syntheses. Optical characterization is carried out using absorption and photoluminescence spectroscopy.
We study the assembly patterns formed by nanocrystals on different substrates and we devise ways to integrate nanocrystals into nanoscale devices.
Fluorescence spectroscopy of nanoparticles
Under continuous illumination, semiconductor nanocrystals have been observed to emit light intermittently. This light intermittency is often called "blinking" and exhibits particular statistics.
We study nanocrystal blinking and in particular the effects of particle geometry and its environment on fluorescence properties. Recently, we studied the blinking properties of single CdSe core and core/shell nanorods.
Nanofabrication (nanogaps and TEBAL)
Nanoscale electronic devices are fabricated and characterized using electron-beam lithography and transmission electron microscopy. Recently, we demonstrated that transmission electron beams can be used to nanosculpt thin metal films to make integrated devices with sub-10 nm features..
Low-noise charge transport in nanoscale structures and electronic devices (transistors, photovoltaics, memory, etc.)
Atomic- and electric-force microscopy of mesoscopic and nanoscale structures.
Equipment and shared facilities at Penn
If you are interested in working with us as an undergraduate student, graduate student, or a postdoc please contact Prof. Marija Drndic at drndic(at)physics.upenn.edu.
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2010, Marija Drndic