Steven Koester

Professor Steven Koester

Steven Koester

Russell J. Penrose Professor in Nanotechnology, Department of Electrical and Computer Engineering


Kenneth H. Keller Hall
Room 5-153
200 Union Street Se
Minneapolis, MN 55455


Ph.D., Electrical & Computer Engineering, 1995, University of California, Santa Barbara, CA, USA
M.S., Electrical Engineering, 1991, University of Notre Dame, Notre Dame, IN, USA
B.S., Electrical Engineering, 1989, University of Notre Dame, Notre Dame, IN, USA

Professional Background

Nano-scaled electronic, photonic, spintronic and sensing devices with an emphasis on emerging material systems

Research Interests

Koester Research Group Site

The Koester NanoDevice Laboratory's (KNDL) mission is to research new solid-state device concepts spanning multiple material platforms and applications. Our lab works on advanced electronic devices, including scaled MOSFETs for end-of-roadmap VLSI applications, cryogenic CMOS, RF transistors, diodes and varactors, and high-power transistors. We also explore novel optoelectronic devices, with an emphasis on advanced photodetectors, and optical modulators. We have also recently explored the spintronic applications of graphene for use in all-spin logic, and miniaturized magnetic field sensors in hard drive read heads. Finally, KNDL has a strong program in biosensors, including glucose monitors, breath sensors, and dosimeters for radiation cancer therapy.

KNDL explores these novel devices mainly through the use of new materials. We have a strong focus on two-dimensional (2D) materials, including graphene, transition metal dichalcogenides (TMDs), and black phosphorus, and have dedicated growth, transfer, and assembly capabilities for these materials. Through our many collaborators at the University of Minnesota Twin Cities and elsewhere, we are also exploring numerous oxide-based materials including the perovskites, gallium oxide, and Hf-based ferroelectrics.  Finally, we maintain a strong capability for traditional Si-based based MOSFET fabrication.  Our work has been supported by a wide range of sources, including government (e.g., NSF, AFOSR, NIH), industry, state, and charitable foundations.

KNDL pursues its research goals through theoretical analysis, device design and simulation, process development, fabrication, and characterization.  All our group members fabricate devices in the Minnesota Nano Center (MNC) cleanroom, and gain a full range of skills necessary to pursue a career in industry or academia.

Teaching Subjects
EE 8950 Advanced Semiconductor Transistors
EE 5163 Semiconductor Properties and Devices I
EE 4951 Senior Design Project
EE 3161 Semiconductor Devices
EE 3101 Circuits and Electronics Lab I

Honors and Awards

2022 Optica (formerly OSA) Fellow for technical innovations in emerging optoelectronic devices, particularly those involving group-IV and 2D-material-based photodetectors and optical modulators
2017 IEEE Fellow for contributions to group-IV electronic and photonic devices
2009 Keynote Speaker at 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT 2009)
2006-2009 Device Research Conference Technical Program Committee, 2009 Conference General Chair
Served on numerous conference organizing/technical program committees
10 IBM Patent Plateau Awards 

Selected Publications

L. Jin and S. J. Koester, “High-performance dual-gated single-layer WS2 MOSFETs with Bi contacts,” IEEE Elect. Dev. Lett43, 639-642 (2022).

J. Wen, V. R. S. K. Chaganti, T. K. Truttmann, F. Liu, B. Jalan, and S. J. Koester, “SrSnO3 metal-semiconductor field-effect transistor with GHz operation,” IEEE Elect. Dev. Lett42, 74-77 (2021).

J. Hu, G. Stecklein, D. A. Deen, Q. Su, P. A. Crowell, and S. J. Koester, “Scaling of the nonlocal spin and baseline resistances in graphene lateral spin valves,” IEEE Trans. Elect. Dev66, 5003-5010 (2019).

R. Ma, H. Zhang, Y. Yoo, Z. P. Degregorio, L. Jin, P. Golani, J. G. Azadani, T. Low, J. E. Johns, L. A. Bendersky, A. V. Davydov, and S. J. Koester, “MoTe2 lateral homo-junction field-effect transistors fabricated using flux-controlled phase engineering,” ACS Nano 13, 8035-8046 (2019).

A. Barik, Y. Zhang, R. Grassi, B. P. Nadappuram, J. B. Edel, T. Low, S. J. Koester, and S.-H. Oh, “Graphene-edge dielectrophoretic tweezers for trapping of biomolecules,” Nat. Commun8, 1867 (2017).

Y. Zhang, R. Ma, X. Zhen, Y. C. Kudva, P. Bühlmann, and S. J. Koester, “Capacitive sensing of glucose in electrolytes using graphene quantum capacitance varactors,” ACS Appl. Mater. Interfaces 9, 38863-38869 (2017).

C. U. Kshirsagar, W. Xu, Y. Su, M. C. Robbins, C. H. Kim, and S. J. Koester, "Dynamic memory cells using MoS2 field-effect transistors demonstrating femtoampere leakage currents,” ACS Nano 10, 8457-8464 (2016).

J. Kim, A. Paul, P. A. Crowell, S. J. Koester, S. S. Sapatnekar, J.-P. Wang, and C. H. Kim, “Spin based computing: device concepts, current status, and a case study on a high performance microprocessor,” Proc. IEEE 103, 106-130 (2015).

N. Haratipour, M. C. Robbins, and S. J. Koester, “Black phosphorus p-MOSFETs with 7-nm HfOgate dielectric and low contact resistance,” IEEE Elect. Dev. Lett36, 411-413 (2015).

N. Youngblood, C. Chen, S. J. Koester, and M. Li, “Waveguide-integrated black phosphorus photodetector with high responsivity and low dark current,” Nature Photon9, 247-252 (2015).

D. A. Deen, E. J Olson, M. A. Ebrish, and S. J. Koester, “Graphene-based quantum capacitance wireless vapor sensors,” IEEE Sensors Journ14, 1459-1466 (2014).

S. J. Koester and M. Li, “High-speed waveguide-coupled graphene-on-graphene optical modulators,” Appl. Phys. Lett. 100, 171107 (2012).

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