Fatemeh (Shadi) Shahedipour-Sandvik

Wide Band Gap Optronix Lab

• High frequency/power electronics 
• Energy: Photovoltaic, Beta(photo)voltaic, solar cells
• Detectors
• Chemical and Biosensors
• Nanostructures and Nanodevices
• Wide band gap materials
• Metalorganic vapor phase Epitaxy of compound semiconductors

Professor Shahedipour-Sandvik's research is focused on development of wide bandgap III-Nitride electronic, optoelectronic, and sensing materials and devices for a variety of application including Energy, high frequency/power electronics, emitters, photon detection, and chemical and biosensors.

III-Nitride materials are of high importance for devices that find a variety of applications, including those mentioned previously. The intrinsic properties of the material including the presence of high polarization field (and piezoelectricity at heterointerfaces), its wide and direct band gap, and the ability for tuning the bandgap within a wide range (0.9 eV-6.2 eV) has been enabling and continues to impact development of structures with additional functionalities, higher performance and novel applications.

Our focus and technical approach is on creating a closed-loop between growth and understanding materials properties and new/optimized device development-grounded in theoretical modeling. On the materials development front, we use MOCVD (metallographic chemical vapor deposition) growth technique to develop high quality, dislocation free/reduced polar, semipolar and non-polar (Al,In,Ga)N layers on native and foreign substrates, and selective area epitaxy of micro- and nano-structures; use a variety of in-situ and ex-situ characterization to understand materials properties including its stress state and evolution, and develop theoretical models such as DFT and molecular dynamics to better understand and guide materials growth development. On the device development front, we have a large emphasis on modeling of device structures using physics-based Sentaurus TCAD modeling, with a recent addition of Monte Carlo modeling for carrier transport studies. Energy band engineering has proven to enable a variety of novel device structures in III-Nitrides including our current effort in APD and Cs-free photocathode development. Our current and on-going research focus includes development of Cs-free photocathodes for applications in astronomy, avalanche photodetectors, beta(/photo)voltaic batteries, thermoelectric, high power electronics, stretchable power electronics, and biosensor for cancer research.

1. Single Photon Counting UV Solar-Blind Detectors using Silicon and III-Nitride Materials
   S. Nikzad; M. Hoenk; A. Jewell; J. Hennessy; A. Carver; T. Jones; T. Goodsall; E. Hamden; P. Suvarna; J. Bulmer; F. Shahedipour-Sandvik; E. Charbon; P. Padmanabhan; B. Hancock; L.D. Bell 
   Sensors 16, 927 (2016) , doi: 10.3390/s16060927
2. MOCVD growth of N-polar GaN on on-axis sapphire substrate: impact of AlN nucleation layer on GaN surface hillock density 
   J. Marini; J. Leathersich; I. Mahaboob; J. Bulmer; N. Newman; F. Shahedipour-Sandvik 
   Journal of Crystal Growth 442, 25-30 (2016) 
   doi: 10.1016/j.j.jcrysgro.2016.02.029
3. Visible-Blind Avalanche Photodetector heterostructure Device Design with Superior Field Confinement and Low Operating Voltage 
   J. Bulmer; P. Suvarna; J.M. Leathersich; J. Marini; I. Mahaboob; N. Newman; F. Shahedipour-Sandvik 
   IEEE Photonics Technology Letters 28, 39-42 (2015) 
   doi: 10.1109/LPT.2015.2479115
4. Avalanche Photodiodes via Atomic Layer Deposition 
   J. Hennessy; L. D. Bell; S. Nikzad; P. Suvarna; F. Shahedipour-Sandvik 
   NASA Tech Brief 38, 12 (2014)
5. Ion implantation based edge termination to improve III-nitride APD reliability and performance 
   P. Suvarna; J. Bulmer; J.M. Leathersich; J. Marini; I. Mahaboob; J. Hennessy; L.D. Bell; S. Nikzard; F. Shahedipour-Sandvik 
   IEEE Photonics Technology Letters 99, 1 (2014) 
   doi: 10.1109/LPT.2014.2382611
6. Influence of buffer layer coalescence on stress evolution in GaN grown on ion implanted AlN/Si(111) substrates 
   J. Gagnon; J. Leathersich; F. Shahedipour-Sandvik; J. Redwing 
   Journal of Crystal Growth 393, 98-102 (2014) 
   doi: 10.1016/j.jcrysgro.2013.08.031
7. Deposition of GaN films on crystalline rare earth oxides by MOCVD 
   Jeffery M. Leathersich; E. Arkun; A. Clark; P. Suvarna; J. Marini; R. Dargis; F. (Shadi) Shahedipour-Sandvik 
   Journal of Crystal Growth 399, 49-53 (2014) 
   doi: 10.1016/j.jcrysgro.2014.04.015
8. GaN Power Schottky Diodes with Drift Layers Growth on Four Substrates 
   R.P. Tompkins; J.R. Smith; K.W. Kirchner; J. Leach; K. Udwary; E. Preble; P. Suvarna; J. Leathersich; F. Shahedipour-Sandvik 
   Journal of Electronic Materials 43, 850-855 (2014)  
   doi: 10.1007/s11664-014-3021-9
9. Enhanced performance of an AlGaN/GaN high electron mobility transistor on Si by means of improved adatom diffusion length during MOCVD epitaxy 
   Shahedipour-Sandvik, F.; Leathersich, J.; Tompkins, R. P.; Suvarna, P.; Tungare, M.; Walsh, T. A.; Kirchner, K. W.; Zhou, S.; Jones, K. A. 
   Semiconductor Science and Technology 28, 074002 (2013) 
   doi: 10.1088/0268-1242/28/7/074002
10. Modification of dislocation behavior in GaN overgrown on engineered AlN film-on-bulk Si substrate 
    Tungare, Mihir; Weng, Xiaojun; Leathersich, Jeffrey M.; Suvarna, Puneet; Redwing, Joan M.; Shahedipour-Sandvik, F. (Shadi) 
    Journal of Applied Physics 113, 163108 (2013) 
    doi: 10.1063/1.4798598
11. Homoepitaxial growth of non-polar AlN crystals using molecular dynamics simulations 
    Leathersich, Jeff; Suvarna, Puneet; Tungare, Mihir; Shahedipour-Sandvik, F. (Shadi) 
    Surface Science 617, 36-41 (2013) 
    doi: 10.1016/j.susc.2013.07.017
12. Growth of GaN by MOCVD on Rare Earth Oxide on Si(111) 
    E. Arkun; R. Dargis; A. Clark; R. Smith; M. Lebby; J.M. Leathersich; F. Shahedipour-Sandvik 
    ECS Transactions 58, 455-461 (2013) 
    doi: 10.1149/05804.0455ecst
13. Ion-Implantation-Induced Damage Characteristics Within AlN and Si for GaN-on-Si Epitaxy 
    Leathersich, Jeffrey M.; Tungare, Mihir; Weng, Xiaojun; Suvarna, Puneet; Agnihotri, Pratik; Evans, Morgan; Redwing, Joan; Shahedipour-Sandvik, F. 
    Journal of Electronic Materials 42, 833-837 (2013) 
    doi: 10.1007/s11664-013-2491-5
14. Design and Growth of Visible-Blind and Solar-Blind III-N APDs on Sapphire Substrates 
    Suvarna, Puneet; Tungare, Mihir; Leathersich, Jeffrey M.; Agnihotri, Pratik; Shahedipour-Sandvik, F.; Bell, L. Douglas; Nikzad, Shouleh 
    Journal of Electronic Materials 42, 854-858 (2013) 
    doi: 10.1007/s11664-013-2537-8
15. HVPE GaN for high power electronic Schottky diodes 
    Tompkins, Randy P.; Walsh, Timothy A.; Derenge, Michael A.; Kirchner, Kevin W.; Zhou, Shuai; Nguyen, Cuong B.; Jones, Kenneth A.; Mulholland, Gregory; Metzger, Robert; Leach, Jacob H.; Suvarna, Puneet; Tungare, Mihir; Shahedipour-Sandvik, Fatemeh (Shadi) 
    Solid-State Electronics 79, 238-243 (2013) 
    doi: 10.1016/j.sse.2012.07.003
16. A Tersoff-based interatomic potential for wurtzite AlN 
    Tungare, Mihir; Shi, Yunfeng; Tripathi, Neeraj; Suvarna, Puneet; Shahedipour-Sandvik, Fatemeh (Shadi) 
    Physica Status Solidi A 208, 1569-1572 (2011) 
    doi: 10.1002/pssa.201001086
17. AlGaN based III-nitride tunnel barrier hyperspectral detector: Effect of internal polarization 
    Tripathi, N.; Bell, L. D.; Shahedipour-Sandvik, F. 
    Journal of Applied Physics 109, 124508 (2011) 
    doi: 10.1063/1.3599878
18. The effect of carbon impurities on lightly doped MOCVD GaN Schottky diodes 
    Tompkins, Randy P.; Walsh, Timothy A.; Derenge, Michael A.; Kirchner, Kevin W.; Zhou, Shuai; Nguyen, Cuong B.; Jones, Kenneth A.; Suvarna, Puneet; Tungare, Mihir; Tripathi, Neeraj; Shahedipour-Sandvik, Fatemeh (Shadi) 
    Journal of Materials Research 26, 2895-2900 (2011) 
    doi: 10.1557/jmr.2011.360
19. Novel Cs-free GaN Photocathodes 
    N. Tripathi; L.D. Bell; S. Nikzad; M. Tungare; P. Suvarna; F. Shahedipour-Sandvik 
    Journal of Electronic Materials 40, 382 (2011) 
    doi: 10.1007/s11664-010-1507-7
20. Effect of n(+)GaN cap polarization field on Cs-free GaN photocathode characteristics 
    Tripathi, N.; Bell, L. D.; Nikzad, S.; Shahedipour-Sandvik, F. 
    Applied Physics Letters 97, 052107 (2010) 
    doi: 10.1063/1.3476341
21. Turn-on voltage engineering and enhancement mode operation of AlGaN/GaN high electron mobility transistor using multiple heterointerfaces 
    Tripathi, N.; Jindal, V.; Shahedipour-Sandvik, F.; Rajan, S.; Vert, A. 
    Solid-State Electronics 54, 1291-1294 (2010) 
    doi: 10.1016/j.sse.2010.06.008
22. Computational and experimental studies on the growth of nonpolar surfaces of gallium nitride 
    Jindal, Vibhu; Shahedipour-Sandvik, Fatemeh 
    Journal of Applied Physics 107, 054907 (2010) 
    doi: 10.1063/1.3309840
23. Theoretical prediction of GaN nanostructure equilibrium and nonequilibrium shapes 
    Jindal, Vibhu; Shahedipour-Sandvik, Fatemeh 
    Journal of Applied Physics 106, 083115 (2009) 
    doi: 10.1063/1.3253575
24. Density functional theoretical study of surface structure and adatom kinetics for wurtzite AlN 
    Jindal, Vibhu; Shahedipour-Sandvik, Fatemeh 
    Journal of Applied Physics 105, 084902 (2009) 
    doi: 10.1063/1.3106164
25. Density functional calculations of the strain effects on binding energies and adatom diffusion on (0001) GaN surfaces 
    Grandusky, J. R.; Jindal, V.; Raynolds, J. E.; Guha, S.; Shahedipour-Sandvik, F. 
    Materials Science and Engineering B 158, 13-18 (2009) 
    doi: 10.1016/j.mseb.2008.12.042

“Formation of highly dislocation free compound semiconductor on a lattice mismatched substrate”, F. Shahedipour-Sandvik, D. Wu, M. Jamil, US8889530

• “Research Foundation Presidential Faculty Fellow”, State University of New York 2013.
• SUNY “Provost Fellow for Doctoral Institutions and Research”, 2012.
• “Visiting Lecturer”, Pure and Applied Physics, University of Tsukuba, Japan, 2012.
• “Excellence in Research” award, State University of New York-Albany, 2012.
• “Blavatnik Award for Young Scientist”, Nominated, NY Academy of Sciences, 2009.
• “25 Individuals who make a difference”, Albany Times Union, Albany, NY, 2008.
• “Women of Excellence in Emerging Professions” award, Albany-Colonie Chamber of Commerce, 2007.
• “Outstanding Paper Award”, Solid State Lighting Materials and Devices, Materials Research Society, 2006.
• “Rising to Lead Best Technologist Award”, Alliance of Technology and Women (ATW), Albany, NY 2006.
• “Governor Woman of Excellence Award”, NY Governor Office, Albany, NY 2005.
• “Best Poster Award”, New Energy New York Symposium, Albany, NY, 2006.
• “Promising Inventor Award”, The Research Foundation of SUNY, 2003.