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    Sands Research Group

  • Nanotechnology

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    Heterogeneous Materials Integration

Research scope


The Heterogeneous Integration Research Group is focused on the understanding and development of processes for the integration of dissimilar materials at both the micro and nano scales to enable the fabrication of novel microsystems, devices and nanocomposite materials.

Hierarchical Heterogeneous Integration


Any practical complex machine must be assembled and integrated at multiple scales, ranging from nano, to micro, to macro. The nanoscale provides opportunities for enhanced materials performance, the microscale brings various materials platforms together, and the macroscale enables interaction with the outside world.

Research areas


Current research areas include solid-state lighting, thermoelectric cooling, thermionic and thermoelectric approaches to direct electrical power generation, nanoelectronics, and macroelectronics. Major themes include laser processing (deposition, etching, bonding and layer transfer), heteroepitaxy, nitride nanostructures, nanostructured solid-state energy conversion devices, and electrochemical synthesis of self-organized nanostructures.

Recently published


"Controlled Growth of Ordered Nanopore Arrays in GaN", I.H. Wildeson, D.A. Ewoldt, R. Colby, E.A. Stach and T.D. Sands, Nano Letters 11, pp. 535-540, (2011).



click here to see a full list of publications

Feel free to contact us

About Us



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Timothy D Sands

Tim is currently the Executive Vice President for Academic Affairs and Provost. His research group's efforts are directed toward the development of novel nanocomposite materials for applications in solid-state lighting, direct conversion of heat to electrical power, and thermoelectric refrigeration.
[personal website]

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Jeremy Schroeder

Jeremy is a Senior Research Associate and Materials Engineering PhD student. He received a BS from The Ohio State University in 1998 and an MS from the University of California, Berkeley in 2002, both in Materials Science and Engineering. His PhD research is focused on nitride-based metal-semiconductor superlattices for thermionic energy conversion.

Graduate students

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Robert Wortman

Rob is a PhD student in Electrical and Computer Engineering. He received a BS in 2004 and an MS in 2006, both in electrical engineering from Purdue University. His research focuses on solid state thermionic transport in rocksalt materials systems for thermoelectric applications. The main research thrust is optimizing the electrical and materials properties of ScN for use as a semiconductor barrier layer in thermionic emission devices.

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Polina Burmistrova

Polina is a PhD student in Electrical and Computer Engineering. She received her MS in Engineering in 2000 from the Moscow State Institute of Radioengineering, Electronics and Automation. Polina then worked in the Electron Microscopy Laboratory of the Moscow Institute of Crystallography Russian Academy of Science followed the Asbestos TEM Labs (TEM analyst) in Berkeley, California. Her PhD research is focused on nitride metal/semiconductor superlattices for thermoelectric applications.

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Caitlin B. Wildeson

Caitlin is an MS student in Material Engineering. She received her BS in Mathematics and Applied Physics from Shippensburg University of Pennsylvania. Her research includes the growth and characterization of thin film epitaxial perovskite structured ferroelectric oxides grown via pulsed laser deposition, with a special focus on structural characterization using high-resolution x-ray diffraction and reciprocal space mapping.

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Yuefeng Wang

Yuefeng is a PhD student in Materials Engineering. He received a BS in Materials Science and Engineering from the University of Science & Technology, Beijing, China in 2008. From 2008-2010 he worked on a CTRC project focused on thermoelectric generation from waste heat in electronic systems. His research interests include thermoelectric device fabrication and modeling, electrochemistry, and nanowires.

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Pankaj Jha

Pankaj is a PhD student in Electrical and Computer Engineering. He received a BS with honors in Electrical Engineering from RGPV University, India and an MS in ECE at Purdue. He worked as a National research fellow in the Electrical Engineering Microelectronics Group at IIT Bombay, India from 2006-2007 and he was a visiting scholar at IMEC, Belgium in Summer 2008. His PhD research interest includes p-type perovskite oxide metal/semiconductor superlattices for thermoelectric applications.

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Bivas Saha

Bivas is a PhD student in in Materials Engineering. His research efforts are primarily directed towards examining nano-structured materials for their potential thermoelectric and spintronic applications. He is currently working on the growth, characterization, measurement of physical properties, and modeling of nitride-based dilute magnetic semiconductors and metal/semiconductor superlattices. Prior work includes first-principles based modelling of nano-structured nitride superlattices for thermoelectric applications.

Undergraduate students

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Jessica Powell

Jessica is a junior in Aerospace Engineering. She is currently working on nanowire thermoelectric devices as part of the Discovery Park Undergraduate Research Internship (DURI) program.

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Nicholas DeNardo

Nic is a sophomore in the Materials Engineering department. He is currently working on nanowire thermoelectric devices as part of the Discovery Park Undergraduate Research Internship (DURI) program.





Purdue's e-Pubs site provides up to date listings of publications from Purdue authors.

Refereed Journals and Proceedings


  • Refereed Publications: Archival Journals
  • Refereed Conference and Symposium Proceedings

Additional publications and talks


  • Invited Talks, Contributed Presentations, etc
  • Non-refereed Proceedings and Technical Reports
  • Books and Book Chapters


Tim Sands currently holds 15 U.S. patents



Composition modulated nanowire arrays for thermoelectric power generation (ONR)

The best nanostructured p-type (Bi,Sb)2Te3 bulk materials utilize nanoscale grain size to enhance phonon scattering, thereby increasing ZT. Nanowire arrays provide similar phonon scattering mechanisms, but the nanowire topology also allows for compositional grading, nanoscale composition modulation, and modulation doping for enhanced electron or hole mobility. The nanowire arrays for this grant are fabricated via electrodeposition in novel branched porous anodic alumina templates.

NSF/DOE Thermoelectrics Partnership: Thermoelectrics for Automotive Waste Heat Recovery (NSF/DOE)

This project focuses on the key elements for the development and deployment of commercial automotive thermoelectric generators. In addition to the work of our collaborators, the Sands group is exploring new nano-structured materials using low-cost and widely available materials towards the development of TE materials with sufficiently high ZT.

Nanostructured Metal/Semiconductor Materials for Thermoelectric Generators (DARPA)

The Sands group focuses on nitride metal/semiconductor superlattices towards the goal of demonstrating a maximum ZT exceeding 2.5 for a metal-semiconductor nanocomposite material with thickness greater than 50 microns. Nitride metal/semiconductor superlattice materials are good candidates for thermionic (energy filtering) materials suitable for the high-temperature (T>700K) segments of thermoelectric generators.

AIN High-Q MEMS FBAR (Film Bulk Acoustic Resonator) in a Liquid Environment (NSF TIE)

Piezoelectric MEMS (Micro-Electro-Mechanical-Systems)-based film bulk acoustic resonators (FBARs) have been shown sensitive to surface mass change, making them a promising sensor for non-labeling biomaterials detection. This project aims to develop a micromachined piezoelectric AlN based FBAR for improved detection sensitivity in a liquid environment. Our collaborators previously demonstrated a 13x - 19x improvement in Q over previously reported FBARs in liquids.

Archive: Grants and Contracts

Click here for a complete list of grants and contracts.



Parijat Deb

MRS Graduate Student Silver Award

“Schottky, p-n Junction and Light Emitting Diodes Employing (In,Ga)N Nanorod Heterostructures,” by P.P. Deb, H. Kim, Y. Qin, R. Lahiji, M. Oliver, D. Ewoldt, R. Reifenberger and T. Sands, 2007 MRS Spring Meeting, San Francisco, CA; paper DD13.8 presented by Parijat Deb, San Francisco, CA, April 12th, 2007.

Aaron Franklin

First Place Poster Prize

“Semi-Vertical SWNT FETs: Steps towards Verticality and Manufacturability,” A.D. Franklin, J.T. Smith, T.D. Sands, T.S. Fisher and D.B. Janes Nano and Giga Challenges in Electronics and Photonics (NGC2007), Phoenix, AZ; presented by A.D. Franklin, 3/15/07.

Aaron Franklin

MRS Graduate Student Silver Award

“Lithography-free In Situ Ohmic Contacts to Single-Walled Carbon Nanotubes,” A.D. Franklin, J.T. Smith, M.R. Maschmann, D.B. Janes, T. Sands and T.S. Fisher, Symposium Q, 2006 Fall MRS Meeting, Boston, MA; presented by A.D. Franklin, Boston, MA, 11/28/06.

Archive: Awards

Click here for a complete list of awards.



  • Tim Sands ratified as Purdue Provost

    February 11, 2011

    Tim Sands is the next executive vice president for academic affairs and provost. As executive vice president for academic affairs and provost, Sands will be responsible for oversight of all Purdue colleges and schools, the regional campuses, and related academic activities in coordination with the Office of the President. The provost also oversees libraries, cultural centers and student services, which includes admissions, registrar, financial aid and health facilities. Click on the link below for more information

    Link to Purdue article

    Tim Sands: 2010 IEEE Fellow

    January 1, 2010

    Tim Sands earned the prestigious distinction of IEEE Fellow in 2010.



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