Birck Nanotechnology Center

Investigators: Jason Clark

Public Description: A new technique to design RF, microwave and mm-wave power amplifiers using partially depleted Si-on-Insulator (SOI) based technology. By isolating transistors from each other either through using a trench etching or a trench oxide, the transistors and their biasing and RF feeding network are stacked on top of each other. Allowing for improved performance in terms of output power and efficiency compared to other techniques.

Investigators: Saeed Mohammadi

Investigators: Jason Clark

Public Description: Current interest in electromagnetic metamaterials has been motivated to a large extent by the recent work on cloaking and transformation optics. Unfortunately, it is difficult to develop metamaterials with low losses and broadband performance and it is especially severe in the visible frequency range, where obtaining good magnetic performance is challenging. Researchers at Purdue University have developed an innovative method that demonstrates that metamaterial devices require anisotropic dielectric permittivity and magnetic permeability can be emulated by specially designed tapered waveguides. This approach leads to a low-loss, broadband performance in the visible frequency range, which is difficult to achieve by other means. An advantage of this technology include that it is able to achieve electromagnetic cloaking in the visible frequency range on a scale 100 times larger than the wavelength.

Investigators: Vladimir Shalaev, Alexander Kildishev

Funded By: BAE Systems

Public Description: Purdue researchers have developed a method of designing the optimum thickness of the layers of a Zinc Selenide Gallium Arsenide super lattice. This type of super lattice structure is key to solid-state light emitting diodes (LED's) and solar cells.

Investigators: Jerry Woodall and Gerhard Klimeck

Public Description: Efficient heat transfer is a continuing struggle for many devices produced today. Moving heat from sources such as electronics and refrigeration units to engines and solar cells is becoming more and more of an issue when optimum performance is at stake. Carbon Nanotubes (CNT) technology has been sought to give enhanced heat transfer properties to these device; however, they inthemselves have limitations as a traditional CNT has not been fully optimized. Inventors at Purdue have developed a new approach using CNTs for significantly increased thermal and electrical conduction. This invention consists of synthesizing a CNT array on various substrates such as Si or Cu and subsequently introducing electron donating or accepting molecular species to the array. By altering the charge density of the nanotubes the electronic contribution to thermal conductance of an interface can be greatly enhanced beyond current levels.

Investigators: Timothy Fisher, Baratunde Cola, Stephen Hodson

Public Description: In microfluidics, there exists a need for a valve that relieves the gas in a microchannel for a gas-liquid phase fluid. This valve should have low technical threshold and no interference with the existing microfluidic chips in order to be applicable. Purdue researchers have developed a novel purge valve that can be used for fluid alightmnet in a microfluidic chip, to eliminate air gaps or bubbles between fluids for a micromixer, and to adjust the flow speed in a microchannel passively. This valve is better than current valves on the market because it can automatically align fluid without sensing feedback, of its cheap and simple fabrication, and of its ease of use.

Investigators: Han-Sheng Chuang and Steve Wereley

Funded By: National Science Foundation (D.C.)

Public Description: Programmable lab-on-a-chip (PLoC) technology does not allow for the same methods of fluid mixture as in traditional lab-on-a-chip (LoC) technology. LoCs use channels with different dimensions and external metering techniques to ensure accurate mixing of fluids. In PLoC technology, all of the channels must have fixed cross-section dimensions and the fluids may be generated in intermediate steps eliminating the ability for external fluid metering. Purdue researchers have developed a novel method for variable volume mixing and automatic fluid management for PLoCs.

Investigators: Ahmed Amin, Han-Sheng Chuang, Steve Wereley, Mithuna Thottethodi, Terani Vijaykumar, and Stephen Jacobson

Funded By: National Science Foundation (D.C.)

Public Description: Researchers at Purdue University are developing new methods in imaging and spectroscopy. This new invention couples the precision of atomic force microscopy with magnetic resonance imaging to allow for single cell imaging of living biological materials. This technology will allow researchers to gather nanoscale information on the surface and subsurface levels of individual cells.

Investigators: Babak Ziaie and Corey Neu

Public Description: Fabrication of nanochannels is attracting considerable interest due to its broad applications in nanobiotechnology and distinct advantages compared to more commonly used nanopores. Nanochannels allow for a slower translocation and multiple sensing spots along the channel which improves read-out resolution. However, they require optical and electrical accessibility which has proven difficult to provide. Purdue researchers have developed a novel fabrication technology for a nanofluidic channel that is simple and compatible with CMOS fabrication. Nano-scale electrical contacts are implemented on the channel and a glass cover allows real time microscopic examination.

Investigators: Teimour Maleki, Babak Ziaie and Saeed Mohammadi

Public Description: The continuous rapid development of wireless communication technologies has led to significant growth of radio-frequency (RF) and microwave devices and systems for both civilian and military applications. While digital technologies have enhanced signal processing capabilities at base-band of the modern communications receiver, there is a need to increase the frequency agility and flexibility of the receiver front-ends. Currently front-end filters for communications receivers have a fixed center frequency and bandwidth (band pass (stop) characteristics). Currently, in order to give such front-ends improved frequency agility, multiple fixed filters with different band pass characteristics are utilized in a switchable arrangement. This method is bulky, costly and may be slow to respond.

Researchers at Purdue University have come up with a novel design for a front-end bandpass filter that has both an electrically tunable center frequency and bandwidth. This electrically tunable filter can replace several fixed filters.

Investigators: Xiaoguang Liu, Dimitrios Peroulis, William Chappell

Funded By: Defense Advanced Research Projects Agency (DARPA), BAE Systems

Public Description: Researchers at Purdue University have developed a new method of fabricating Gallium Nitride (GaN) nanorods which have pores a variable size running through the center of each nanorod. These pores connect to channels below that connect the nanorods together and to outside structures. The nanorods can be tuned with a nanopore diameter ranging from from 10 nm -100 nm. Another benefit of this technology is the ability to utilize the GaN walls of the nanopore for biosensing. As GaN is a semiconductor, this technology can take advantage of an electrical interface between the biological agent and the porous nanorod. Current nanopores used for DNA sequencing have insulating pore walls so they do not have this additional detection method. In addition to DNA sequencing, applications may also include ion channel studies in cellular walls, and near-field imaging. Similar structures are currently being used for DNA sequencing but they require much more processing than what is required by this technology while also not offering the additional biosensing capabilities.

Investigators: Isaac Wildeson, Timothy Sands

Funded By: DOE - Department of Energy, DOD/USAARL - U.S. Department of Defense

Public Description: Purdue researchers have developed a novel method of improving inversion layer mobility in metal oxide semiconductor field effect transistors (MOSFET) by electrostatic interface smoothing. This method increases the mobility in silicon carbide (SiC) MOSFETS by 2-3 times, thereby reducing resistance and increasing efficiency.

Investigators: James Cooper, Jr., Barbara Cooper, John Williams

Funded By: (ARDEC) US Army Armaments Research, Development a

Public Description: Purdue researchers have developed a novel method of enabling digital logic circuits using graphene field effect transistors (FET) which could lead to much faster integrated circuits compared to using silicon.

Investigators: James Cooper, Jr. and Joerg Appenzeller

Funded By: Intel Corporation

Public Description: Porous anodic alumina (PAA) templates have been widely explored for high-yield and low-cost nanowire array synthesis. The PAA template forms a robust structural framework that is required for device integration, but has the drawback of adding to the parasitic thermal conductance during thermoelectric applications. Furthermore, removing the template from the nanowire array after synthesis causes the array to collapse. Researchers at Purdue University have developed a branched porous anodic alumni (B-PAA) template to overcome this issue. This template allows the fabrication of self-supporting branched nanowire arrays that maintain structural stability after complete removal of the template.

Investigators: Kalapi Biswas and Timothy Sands

Funded By: NAVY/ONR - U.S. Navy Office of Naval Research

Public Description: The use of atomic force microscopy (AFM) devices has been regularly applied to analyze micro- and nano-sized particles. However, their use has been limited to “hard” particles and not been able to be applied to “soft” materials such as liquids and biological samples.
Researchers at Purdue have developed a new class of nano-cantelievers for imagining along with a new method for transduction of the probe motion and sampling. This invention will allow the imaging of these “soft” materials all-the-while providing unprecedented resolution at high speeds plus applying at least 1-2 orders of magnitude less force as compared to current technology. This technology will allow the AFM to be applied to many more material than ever before.

Investigators: Ronald Reifenberger, Arvind Raman, Laura Biedermann and Mehdi Yazdanpanah

Public Description: Researchers at Purdue University have developed a technology to use a cationic surfactant, cetyltrimethylammonium bromide (CTAB), for solution synthesis of Ag, Au, Cu, Pt, CdS, ZnS, and PbS nanoparticles and their subsequent attachment on cellulose nanocrsytals’ surfaces. The same chemistry can be extended to virtually any elemental metallic or binary inorganic compounds that can potentially be synthesized from solution into a nanoparticle form. This novel invention has the potential to benefit a variety of industries that use cellulose based materials, or any industry that can use a process of facile synthesis of stable arrays of inorganic nanoparticles.

Investigators: Lia Stanciu, Robert Moon and Sonal Padalkar

Funded By: US Forest Service - Forest Products Laboratory School of Materials Engineering, Birck Nanotechnology Center

Public Description: Recently, a novel approach for designing tunneling field-effect transistors (TFETs) has been proposed based on vertical tunneling. The vertical TFET also known as gFET, delivers desirable ON-currents much larger than the lateral TFET, but are also characterized by undesirable large OFF-currents. This high OFF-current renders the standard gFET design useless for low power logic applications. Purdue researchers have developed a novel design for a gFET that exhibits an OFF-current several orders of magnitude lower than conventional gFETs. The design provides a high ON-OFF current ratio in addition to a low subthreshold slope. This design concept may be the key element in pushing the gFET towards a viable MOSFET replacement, operating at low voltages and small voltage swings.

Investigators: Mathieu Luisier, Samarth Agarwal and Gerhard Klimeck

Funded By: NSF - National Science Foundation (Arlington), NRI Nanoelectronics Research Initiative, subsidiary of SR, NCN Network for Computational Nanotechnology, NIST - National Institute of Standards & Technology

Public Description: Monitoring in-vivo pressure is a critical element in many medical applications including cancer and glaucoma treatment. However, the interaction of biological materials with the pressure sensors causes the pressure sensors to become highly inaccurate after just a short period of time. Researchers at Purdue University have developed an implantable pressure sensor that eliminates the interaction of cells and other biological materials with the sensor. Thus, in-vivo pressure can be monitored for a much longer time than current methods while maintaining a high accuracy.

Investigators: Babak Ziaie and Teimour Maleki

Funded By: NIH - National Institutes of Health (Rockville)

Public Description: Changes in intraocular pressure (IOP) are harmful to a patient’s eyesight, causing irreversible damage. IOP monitoring is essential in the study and cure of many eye diseases, especially glaucoma. Current monitoring systems are unable to provide continuous monitoring of the patient, and the results are affected by individual patient variances in the eye. Researchers at Purdue University have developed an IOP monitoring system provides a continuous monitoring of IOP, while at the same time, being independent of patient differences.

Investigators: Babak Ziaie, Teimour Maleki, Girish Chitnis and Louis Cantor

Funded By: Alfred E Mann Foundation for Biomedical Engineering

Public Description: Semiconductor nuclear radiation detection is attracting considerable attention in the marketplace due to its broad applications in nuclear physics, x-ray astronomy, gamma ray astronomy, homeland security, and nuclear medicine. Current devices are innaccurate due to high voltage requirements and difficult calibration methods. Researchers at Purdue University have developed a unique microdevice to monitor radiation at a more sensitive and accurate level than current techniques.

Investigators: Babak Ziaie and Teimour Maleki

Funded By: NIH - National Institutes of Health (Rockville)

Public Description: With technology scaling, process imperfections due to sub-wavelength lithography and intrinsic device level variations lead to large variations in transistor parameters. The underlying issue with SRAM design is the conflicting requirement in transistor sizing between read stability and writeability. Purdue researchers have developed a novel architecture-aware, read-access preferred (REAP) design methodology to improve SRAM yield and lower VVIN.

Investigators: Kaushik Roy, Jaydeep Kulkarni, Ashish Goel and Patrick Ndai

Funded By: MARCO - Microelectronics Advanced Research Corporation

Public Description: Purdue University researchers have developed a novel bandpass filter that performs better than the state-of-the-art across significant portions of the filter design space. The proposed device also allows for enhanced performance metric selectivity.

Investigators: Jeffery Rhoads

Funded By: NSF - National Science Foundation (Arlington)

Public Description: Open-Optoelectrowetting technology is currently limited to microfluidic manipulation and its applications. In order for O-OEW technology to be truly useful it will have to be integrated with other technologies in order to offer a range of functions, much like Lab-on-a-Chip devices which incorporate several micro-scale laboratory tools into one device.

Researchers at Purdue University have developed a complimentary O-OEW technology which allows for tunable liquid heating using an O-OEW chip. Heating can be accomplished be either direct heat or heating of the substrate which can then precisely heat the liquid. Integration of this technology would allow for the creation of optically based O-OEW devices with the capabilities of Lab-on-a-Chip devices.

Investigators: Han-Sheng Chuang, Aloke Kumar and Steven Wereley

Funded By: NSF - National Science Foundation (Arlington)

Public Description: When working with very thin layers of liquid materials, the ability to manipulate the area(s) they cover plays a key role in the applications in which each liquid can be used. Open Optoelectrowetting (O-OEW) technology is one way to manipulate fluids on the micro level, but it has several limitations. One such limitation is that forces cannot be uniformly distributed on a fluid, which hurts the overall precision of O-OEW technology.
Researchers at Purdue University have developed a complimentary O-OEW technology which allows for more exact droplet manipulation with an O-OEW chip. Sandwiched O-OEW allows for equal actuation forces to be exerted on a droplet without regards to the direction of the force. This technology allows for increased precision compared to previous O-OEW technologies.

Investigators: Han-Sheng Chuang, Aloke Kumar and Steven Wereley

Funded By: NSF - National Science Foundation (Arlington)

Public Description: When working with very thin layers of liquid materials, the ability to manipulate the area(s) they cover plays a key role in the applications in which each liquid can be used. Open Optoelectrowetting (O-OEW) technologies cannot currently be used in applications which require addressable illumination such as LCD panels.
Researchers at Purdue University have developed a complimentary O-OEW technology which allows for back-side illumination of an O-OEW chip. This technology provides homogeneous illumination throughout a device which allows for the use of O-OEW chips in addressable illumination devices such as LCD panels.

Investigators: Han-Sheng Chuang, Aloke Kumar and Steven Wereley

Funded By: NSF - National Science Foundation (Arlington)

Public Description: Force spectroscopy in AM-AFM can reveal the tip-sample interaction force history in a given cycle of oscillation. This information is very important to AFM experimentalists because it provides quantitative measurements of local properties (elasticity, adhesion) which are essential for advanced surface characterization. They also provide information on imaging forces which need to be minimized when scanning fragile biological samples so as not to irreversibly damage the sample. Quantitative force spectroscopy performed “real-time” while simultaneously scanning the sample in AM-AFM or tapping mode AFM allows for rapid quantitative nanomechanical characterization of the surface, orders of magnitude faster than force- volume modes. In order to measure tip-sample forces in “real time” while scanning the sample in AM-AFM, the cantilever needs to be instrumented with an additional sensor whose output is proportional to the tip-sample force with minimal post-processing needs. Current systems for real-time measurement of tip-sample forces have significant shortcomings in that they are either significantly more expensive than current systems, incompatible with current systems, less sensitive than conventional systems, or much harder to use.
Researchers at Purdue University have developed an alternate means to measure time resolved tip-sample interaction forces in dynamic AFM (dAFM) rapidly while scanning an image in the tapping mode (or any dAFM mode). This technology allows for real-time monitoring of tip acceleration using photodetector channels already available on most commercial AFM designs, provides for easy calibration, could be easily integrated into existing cantilever designs, all-the-while maintaining the cantilevers basic shape and scanning characteristics which allows for compatibility with the vast majority of AFM systems worldwide.

Investigators: Arvind Raman, John Melcher and Ronald Reifenberger

Funded By: Birck Nanotechnology Center and School of Mechanical Engineering

Public Description: Although consumer electronics have transitioned almost entirely to lead (Pb)-free solder interconnects, the new Pb-free interconnects have lower performance characteristics and require higher processing temperatures compared to their Pb containing predecessor. These new interconnects also have the propensity to form tin “whiskers” that increase the risk of short circuits.Purdue researchers have developed a new interconnect technology based on low temperature sintering that replaces traditional solder joints as well as high-Pb and silver (Au) solder alloys used for high temperature attach of semiconductor die to substrate. This technology lowers the processing temperature, improves interconnect characteristics, and minimizes the tin “whiskers”.

Investigators: Carol Handwerker, Suk Kim and Eric Stach

Funded By: USAF-Air Force Research Laboratory, National Science Foundation (D.C.)

Public Description: Researchers at Purdue University developed with funding from the US Air Force, a completely wireless temperature and strain sensors for mechanical seals. This technology is to serve as Background IP for a project funded by Flowserve Corp. The sensors will be integrated on the mechanical seals and will be capable of reading and transmitting the temperature and strain placed on the seal without disturbing its operation; which includes wireless power eliminating the need to interrupt operation for a change of battery.

Investigators: Dimitrios Peroulis

Public Description: This demonstrations shows a SPASER (which uses surface plasmons, whos resonance is capable of squeezing optical frequency oscillations into a nanoscopic cavity) to demonstrate a nanolaser that has overcome the loss of surface plasmons and is detectable in metal nanoparticles.

Investigators: Vladimir Shalaev and Evgueni Narimanov

Funded By: National Science Foundation (D.C.), NASA - National Aeronautics and Space Administration, U.S. Army Research Office

Public Description: In nanomedicine, biodistribution studies are absolutely critical to evaluate the safety and efficacy of any given nanoparticle formulation, but it is unfeasible and impractical to use standard imaging techniques that can only detect agglomerations of nanoparticles in very small areas. Researchers at Purdue University have developed a novel method for single nanoparticle detection that incorporates a short, non-endogenous DNA sequence as a unique “barcode” that can be expanded by in situ PCR and detected by fluorescence or colorimetric methods. Preliminary experiments have demonstrated proof-of-principle of this DNA barcoding method using cell-free systems. This method has the potential to enable the precise analysis of long- term nanoparticle distribution and to accelerate its translation for clinical applications.

Investigators: James Leary and Trisha Eustaquio

Funded By: Bindley Bioscience Center, Birck Nanotechnology Center, Oncological Sciences Center

Public Description: Researchers at Purdue University have developed an innovative invention that allows broad-band onmindirectional light absorption and concentration with nearly 100% efficiency. The device works by forming an effective “black hole” for the incident light due to the spatial variations of the dielectric response of the (meta)material forming its structure. Advantages include that it does not rely on resonance (broadband), is potentially cheaper to manufacture in any quantity, and does not require a magnetic response.

Investigators: Alexander Kildishev and Evgueni Narimanov

Funded By: U.S. Army Research Office

Public Description: The pH meter is a commonly used instrument in many laboratories that perform chemical or biological research. In certain situations, such as monitoring a chemical reaction it is critical to precisely control the pH of the solution. Also, some biological molecules such as enzymes can be detected by directly monitoring the pH shifts. Current pH meters are not sensitive enough to perform in such applications. Researchers at Purdue University have developed a diffraction-based hydrogel grating pH sensor that can be applied in situations where current pH meters fail. This pH meter is more sensitive and can detect small range pH shifts.

Investigators: Cagri Savran, Chun-Li Chang, Babak Ziaie and Zhenwen Ding

Public Description: Current commercialized thermoelectric elements are bulk materials with thermoelectric figure of merit (i.e. ZT) values around one. New thin film thermoelectric materials based on metal- semiconductor (M-S) multilayers are currently being developed in order to improve ZT to levels that will make thermoelectric power generation more practical. Maximum power densities for such M-S multilayers are achieved when thermoelectric leg thicknesses are on the order of 50-200μm. However, due to constraints associated with standard thin film deposition techniques (e.g. sputtering), these M-S multilayers have practical thickness limits of 10-20μm. In addition, optimal M-S multilayer film quality is often achieved for thickness values less than 10μm. Purdue researchers have developed a novel process that overcomes these limits on film thickness in order to improve the figure of merit of thermoelectric materials.

Investigators: Jeremy Schroeder and Timothy Sands

Funded By: Birck Nanotechnology Center, NAVY/ONR - U.S. Navy Office of Naval Research

Public Description: A miniaturized particle separation technique is essential to chip-based biological assays in order to purify samples. Purdue researchers have developed a novel program-controlled cyclic particle extraction technique on an integrated polydimethylsiloxane (PDMS) microfluidic platform.

Investigators: Ahmed Amin, Stephen Jacobson, Han-Sheng Chuang and Steven Wereley

Funded By: Birck Nanotechnology Center, NSF - National Science Foundation (Arlington)

Public Description: There is great interest in the LED industry to move the growth of III-nitride LEDs to silicon substrates, which are available in low-cost, large diameter wafers. Silicon’s absorbance of visible light and its mismatch in both lattice parameter and coefficient of thermal expansion with III-nitride make this transition difficult. Purdue researchers have developed a novel process for fabricating III-nitride based nanopyramid light emitting diodes (LEDs) on a metalized silicon substrate in order to create efficient, low-cost LEDs on silicon.

Investigators: Isaac Wildeson and Timothy Sands

Funded By: DOE - Department of Energy, Birck Nanotechnology Center, TRASK Innovation Award, DOD/USAARL - U.S. Department of Defense