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Fatemeh (Shadi) Shahedipour-Sandvik

Dr. Shadi Shahedipour-Sandvik
Associate Professor of Nanoengineering

Watch Professor Shahedipour-Sandvik's "Inside CNSE" video interview on the capabilities of the environmental scanning electron microscope

Degrees:

  • Ph.D, Experimental Solid State Physics, University of Missouri-Columbia, 1998
Areas of research:
  • Optoelectronics
  • Wide bandgap III-Nitride semiconductor materials and devices
  • Metalorganic chemical vapor deposition technique
Research Website: WBG Optronix Lab

Description of research:

Professor Shahedipour-Sandvik's research is focused on development of high performance wide bandgap III-Nitride optoelectronic materials and devices. The focus of the research in the III-Nitride program is two fold:
  1. Development of ultra low dislocation density AlInGaN layers with an emphasis on nanometer scale structures, homoepitaxial growth, and use of "truly compliant substrate" on Si substrate, the concept of which has been developed in our laboratory; understanding of role of defects in optical and electrical properties of the layers, and
  2. Development of AlInGaN-based optoelectronic devices including UV-Visible detectors with ultra low leakage, UV and Visible LEDs for solid state lighting and HFET structures for RF applications
The applications of devices based on this material system ranges from LEDs for solid state lighting (LEDs) to detectors for military (Space-to-space covert operation), civilian (air and water purification) and scientific (UV astronomy) applications to RF-power devices for communication.

In order to achieve high performance devices, Shahedipour-Sandvik's group has put in place an approach that focuses on developing high quality epitaxial layers though in depth characterization of their structural, optical and electrical signatures; developing device modeling capability to accommodate the desired characteristics and finally epitaxial deposition of the modeled structures and evaluation of their performance. This approach helps complete a loop that feeds information from one step of the study into the next and eventually development of high performance devices with known and predictable characteristics.

In our research we put heavy emphasis on the art of epitaxial growth of GaN-based layers and device structures using Metalorganic Chemical Vapor Deposition (MOCVD) system as well as their evaluation.

Selected Recent Publications:

Computational and Experimental Study on the Growth of non-polar Surfaces of Gallium Nitride
V. Jindal and F. Shahedipour-Sandvik, J. of Applied Physics, 107, 054907 (2010)

Theoretical prediction of GaN nanostructure equilibrium and nonequilibrum shapes
V. Jindal, and F. Shahedipour-Sandvik, J. Appl. Phys. 106, 083115 (2009)

Density functional theoretical study of surface structure and adatom kinetics for wurtzite AlN
V. Jindal and F. Shahedipour-Sandvik, Journal of Applied Physics, 105, 084902 (2009)

Defect-related photoluminescence in Mg-doped GaN nanostructures
M.A. Reshchikov, F. Shahedipour-Sandvik, B. J. Messer, V. Jindal, N. Tripathi and M. Tungare
Physica B, 404, 4903 (2009)

Direct immobilization and hybridization of DNA on group III nitride semiconductors
Xiaobin Xu, Vibhu Jindal, Fatemeh Shahedipour-Sandvik, Magnus Bergkvist and Nathaniel C. Cady
Applied Surface Science, 255, 5905 (2009).

Density functional calculations of the strain effects on binding energies and adatom diffusion on (0001) GaN surfaces
J. R. Grandusky, V. Jindal, J. Reynolds, F. Shahedipour-Sandvik
Materials science & engineering. B, Solid-state materials for advanced technology,158, 13 (2009).

Fully Tunable Hyperspectral Imaging Detector based on III-Nitride Dielectric Heterostructures
L. D. Bell, N. Tripathi, J. R. Grandusky, V. Jindal, F. Shahedipour-Sandvik
IEEE Sensors J., special issue on "Nanosensors for Defense and Security", 8, 724 (2008)

Selective area heteroepitaxy of low dimensional a-plane and c-plane InGaN nanostructures using pulsed MOCVD
V. Jindal, N. Tripathi, M. Tungare, O, Pachos, P. Haldar, and F. Shahedipour-Sandvik
Phys. Stat. Soli. (c), 5, 1709 (2008)

Growth and characterization of a novel hyperspectral detector using the III-nitrides
N. Tripathi, L. D. Bell, J. R. Grandusky, V. Jindal, F. Shahedipour-Sandvik
Phys. Stat. Soli. (c), 5, 2228 (2008)

Effect of strain on AlGaN hexagonal nanostructures by selective area heteroepitaxy
V. Jindal, J. R. Grandusky, N. Tripathi, B. Thiel, F. Shahedipour-Sandvik
Phys. E: low dimensional systems and nanostructure, 40, 478 (2008)

AlGaN based Tunable Hyperspectral Detector
N. Tripathi, J. Grandusky, V. Jindal, F. Shahedipour-Sandvik, D. L. Bell
Appl. Phys. Lett. 90, 231103 (2007)

Identification of important growth parameters for the development of high quality Al>0.5GaN by MOCVD
J. R. Grandusky, M. Jamil, V. Jindal, N. Tripathi, F. Shahedipour-Sandvik,
J. Vac. Sci. Technol. A, 25(3), (2007)

Homoepitaxial growth and electrical characterization of GaN-based Schottky and light-emitting diodes
X. A. Cao, H. Lu, E. B. Kaminsky, S. D. Arthur, J. R. Grandusky, F. Shahedipour-Sandvik
J. Cryst. Growth, 300, 382, (2007)

Mechanism of large area dislocation reduction in GaN layers on AlN/Si (111) by substrate engineering
M. Jamil, J. R. Grandusky, v. Jindal, N. Tripathi, F. Shahedipour-Sandvik,
J. Appl. Phys. 102, 023701 (2007)
Virtual Journal of Nanoscale Science & Technology, 16, 5 (2007)

Selective area heteroepitaxy of nano-AlGaN UV excitation sources for bioflourescence application
V. Jindal, J. R. Grandusky, F. Shahedipour-Sandvik, S. F. LeBouef, J. Balch, and T. Tolliver
"Outstanding MRS Paper Award", J. Mater. Res. 22, 838, (2007)

High resolution x-ray diffraction analyses of ion-implanted GaN/AlN/Si heterostructures
R. J. Matyi, M. Jamil, F. Shahedipour-Sandvik
Phys. Stat. Sol. A, 204, 2598 (2007)

Development of pit-defect free smooth a-plane GaN surfaces on r-plane sapphire using MOCVD: A growth mechanism study
Vibhu Jindal, James Grandusky, Muhammad Jamil, Eric Irissou, Fatemeh Shahedipour-Sandvik, Kevin Matocha, Vinayak Tilak,
Phys. Stat. Sol. (a) 3, 179, (2006)

Reduction of crack and dislocation defects in GaN layers grown on Si substrate by MOCVD using a substrate engineering technique
M. Jamil, E. Irissou, J. R. Grandusky, V. Jindal, and F. Shahedipour-Sandvik,
Phys. Stat. Sol. (c) 3, 1787, (2006)

Development of native, single crystal AlN substrates for device applications
L. J. Schowalter, S. B. Schujman, W. Liu, M. Goorsky, M. C. Wood, J. Grandusky, and F. Shahedipour-Sandvik
Phys. Stat. Sol. (a) 203, 1667 (2006)

Origin of ring defects in high In content green InGaN/GaN MQW: An Ultrasonic Force Microscopy Study
F. Shahedipour-Sandvik, M. Jamil, K.Topol, J. R. Grandusky, K. A. Dunn, J. Ramer and V. N. Merai
Mat. Res. Soc. Inter. J. of Nitride Res. 10, 3 (2005)

Development of Strain Reduced GaN on Si(111) by Substrate Engineering
M. Jamil, J. R. Grandusky, V. Jindal, S. Guha, A. Arif, and F. Shahedipour-Sandvik
Appl. Phys. Lett. 87, 82103 (2005)

Optimization of the active region of InGaN/GaN 405 nm light emitting diodes using statistical design of experiments for determination of interaction effects
J. R. Grandusky, M. Jamil, J. A. Deluca, S. F. LeBoeuf, X. A. Cao, S. D. Arthur and F. Shahedipour-Sandvik
J. Vac. Sci. Tech. 23, B.1576 (2005)

Strain dependant facet stabilization in selective area heteroepitaxial growth of GaN nanostructures
F. Shahedipour-Sandvik, J. R. Grandusky, A. Alizadeh, C. Keimel, S. Taylor, S. LeBoeuf, S. Ganthi, and P. Sharma
Appl. Phys. Lett. 87, 233108 (2005)
Virtual Journal of Nanoscale Science & Technology, 12, 24 (2005)

Microstructural leakage current in GaN/InGaN Light Emitting Diodes
X. A. Cao, J. Teetsov, F. Shahedipour-Sandvik and S. D. Arthur
J. Crystal Growth, 264, 172 (2004)

Efficient GaN Photocathodes for Low-Level Ultra-Violet Signal Detection
F. Shahedipour, B. W. Wessels, M. P. Ulmer, C. Josef, T. Nihashi
IEEE J. of Quantum Electro. 38, 333 (2002)

Defects observed by optical detection of electron paramagnetic in electron-irradiated p-type GaN
L. S. Vlasenko, C. Bozdog, G. D. Watkins, F. Shahedipour and B. W. Wessels
Phys. Rev. B 65, 205202 (2002)

AlGaN for Solar-Blind UV Photodetectors
P. Sandvik, K. Mi, F. Shahedipour, P. Kung, R. McClintock, A. Yasan, and M. Razeghi
J. of Crystal growth 231, 366 (2001)

Comparative Optical Studies of p-type and unintentionally doped GaN
S. Guha, F. Shahedipour, R.C. Keller, V. Yang and B.W. Wessels
Appl. Phys. Lett. 78, 58 (2001)

Lateral Epitaxial Overgrowth of GaN on Sapphire and Silicon Substrates for Ultraviolet Photodetector Applications
M. Razeghi, P. Sandvik, P. Kung, D. Walker, K. Mi, X. Zhang, V. Kumar, J. Diaz and F. Shahedipour
Mat. Sci. and Eng. B74, 107 (2000)

Investigation of the formation of the 2.8 eV luminescence band in p-type GaN:Mg:
F. Shahedipour, and B. W. Wessels
Appl. Phys. Lett. 76, 3011 (2000)

On the origin of the 2.8 eV blue emission in p-type GaN:Mg: A time-resolved photoluminescence investigation
F. Shahedipour and B. W. Wessels
MRS. Int. J. Nitride Semicond. Res. 6, 12 (2001)

Photoluminescence Band Near 2.9 eV in Undoped GaN Epitaxial Layers
M. A. Reshchikov, F. Shahedipour, R. Y. Korotkov, and B. W. Wessels
J. of Appl. Phys., 87, 3351 (2000)

Pressure Dependence of the Blue Luminescence in Mg doped GaN
S. Ves, U. D. Venkateswaran, I. Loa, K. Syassen, F. Shahedipour, B. W. Wessels
Appl. Phys. Lett., 77, 2536 (2000)

Optical Properties of Plasma Species Adsorbed during Diamond Deposition on Steel
F. Shahedipour, B. P. Conner, and H. W. White,
J. of Appl. Phys., 88, 3039 (2000)

Deep Acceptors in Undoped GaN
M. A. Reshchikov1, F. Shahedipour, R.Y. Korotkov, M.P. Ulmer, and B. W. Wessels
Physica B 273-274, 105 (1999)

Low Temperature Synthesis of Diamond-like Carbon Film on Steel Substrates by ECR-PACVD
S. Zhu, F. Shahedipour, and H. W. White
J. American Ceramic Soc., 81, 1041 (1998)

Evidence of Apical Oxygen in Artificially Superconducting SrCuO2- BaCuO2 Thin Films: A Raman Characterization.
S. Zhu, D. P. Norton, J. E. Chamberlin, F. Shahedipour, and H.W. White.
Phys. Rev. B, 54, 1 (1996)

Conference Papers:

Density functional calculations for diffusion path-way and energy barriers determination of precursor adatoms on different crystallographic planes of GaN
V. Jindal, J. R. Grandusky, N. Tripathi, M. Tungare, and F. Shahedipour-Sandvik,
(Accepted for publication, Mat. Res. Soc. Proc. 2008)

Density functional calculations of the binding energies and adatom diffusion on strained AlN (0001) and GaN (0001) surface
V. Jindal, J. R. Grandusky, N. Tripathi, M. Tungare, and F. Shahedipour-Sandvik
Mat. Res. Soc. Symp. Proc. 1040, 1040-Q06-02 (2008)

Development of homoepitaxially grown GaN thin film layers on freestanding bulk m-plane substrates by metalorganic chemical vapor deposition (MOCVD)
V. Jindal, J. R. Grandusky, M. Tungare, N. Tripathi, F. Shahedipour-Sandvik, P. Sandvik, V. Tilak
Mat. Res. Soc. Symp. Proc. Vol. 1040, 1040-Q01-08 (2008)

Ultrafast carrier dynamics and recombination in green emitting InGaN MQW LED
A. N. Cartwright, M. Cheung, F. Shahedipour-Sandvik, J. R. Grandusky, M. Jamil, V. Jindal, C. Wetzel, P. Li, T. Dtchprohm, and J. Nelson
Mat. Res. Soc. Proc. 916, 7 (2006)

Selective area heteroepitaxy of nano-AlGaN UV excitation sources for bioflourescence application
V. Jindal, J. R. Grandusky, F. Shahedipour-Sandvik, S. F. LeBouef, J. Balch, and T. Tolliver
Mater. Res. Soc. Proc. 916, 97 (2006)

Effect of HVPE GaN substrate condition on the characteristics and performance of 405nm LEDs
J. R. Grandusky, M. Jamil, V. Jindal, F. Shahedipour-Sandvik, H. Lu, X._A. Cao, and E. B. Kaminsky
Mater. Res. Soc. Proc. 916, 91, (2006)

Deep green emission at 570nm from InGaN/GaN MQW active region grown on bulk AlN substrate
F. Shahedipour-Sandvik, J. R. Grandusky, M. Jamil, V. Jindal, S. B. Schujman, L. J. Schowalter, R. Liu, F. A. Ponce, M. Cheung, A. Cartwright
SPIE Int. Soc. Opt. Eng., 5941, 37 (2005)

Development of low dislocation and strain reduced GaN on Si(111) by substrate engineering
M. Jamil, J. R. Grandusky, V. Jindal, F. Shahedipour-Sandvik, S. Guha, M. Arif
SPIE Int. Soc. Opt. Eng., 5941, 59411E (2005)

Important interaction effects in the growth of InGaN violet light emitting diodes by MOCVD
J. R. Grandusky, M. Jamil, V. Jindal, J. A. DeLuca, S. F. LeBoeuf, X. A. Cao, S. D. Arthur, F. Shahedipour-Sandvik
SPIE Int. Soc. Opt. Eng., 5941, 144 (2005)

Dislocation reduction and structural properties of GaN layers grown on N+implanted AlN/Si (111) substrates
M. Jamil, J. R. Grandusky, V. Jindal, N. Tripathi and F. Shahedipour-Sandvik
Mat. Res. Soc. Proc. 892, FF22-3.1 (2005)

Effects of GaN template annealing on the optical and morphological quality of the homoepitaxially overgrown GaN layer
James R. Grandusky, Vibhu Jindal, Muhammad Jamil and Fatemeh Shahedipour-Sandvik
Mat. Res. Soc. Proc. 892, FF27-7.1 (2005)

Effect of GaN Surface Treatment on the Morphological and Optoelectronic properties of Violet Light Emitting Diodes
M. Jamil, J. R. Grandusky and F. Shahedipour-Sandvik
Mat. Res. Soc. 831, E1.8.1 (2004)

Influence of defects on electrical and optical characteristics of GaN/InGaN-based light-emitting diodes
Xian-an Cao, K. Topol, F. Shahedipour-Sandvik, J. Teetsov, Peter M. Sandvik, Stephen E. LeBoeuf, Abasifreke Ebong, James W. Kretchmer, Edward B. Stokes, S. Arthur, Alain E. Kaloyeros, D. Walker
SPIE Int. Soc. Opt. Eng., 4776, 105 (2002)

Progress in the fabrication of GaN photocathodes
Melville P. Ulmer, Bruce W. Wessels, Fatemeh Shahedipour, Roman Y. Korotokov, Charles L. Joseph, Tokuaki Nihashi,
SPIE Int. Soc. Opt. Eng. 4288, 246 (2001)

AlxGa1-xN materials and device technology for solar blind ultraviolet photodetector applications
Ryan McClintock, Peter M. Sandvik, Kan Mi, Fatemeh Shahedipour, Alireza Yasan, Christopher L. Jelen, Patrick Kung, Manijeh Razeghi,
SPIE Int. Soc. Opt. Eng., 4288, 219 (2001)

Solar-blind AlxGa1-xN p-i-n photodetectors grown on LEO and non-LEO GaN
Peter M. Sandvik, Danielle Walker, Patrick Kung, Kan Mi, Fatemeh Shahedipour, Vipan Kumar, Xinghong Zhang, Jacqueline E. Diaz, Christopher L. Jelen, Manijeh Razeghi, SPIE Int. Soc. Opt. Eng., 3948, 265 (2000)

In Situ FTIR Spectroscopic Detection of Adsorbed Species on Sapphire Substrate in a Diamond ECR-PACVD System
F. Shahedipour, S. Zhu, and H. W. White,
Mat. Res. Soc. Proc. 502 (1998)

Determination of hydrogen in CVD diamond by notched neutron spectrum technique and FTIR
F. Golshani, W. H. Miller, M. A. Prelas, T. Sung, G. Popovici, G. Manning, S. K. Loyalka, F. Shahedipour. H. W. White, W. D. Brown, A. P. Malshe. and H. A. Naseem, Mat. Res. Soc. Symp. Proc. 416, 361 (1996)

Growth and Characterization of Polycrystalline Diamond Films on Porous Silicon By Hot Filament CVD
S. Mirzakuchak, E.J. Charlson, E.M. Charlson, T. Stacy, F. Shahedipour,
H. W. White
Mat. Res. Soc. Proc., 423 (1996)

Raman and FTIR Study of Neutron Irradiated CVD Diamond
S. Khasawinah, G. Popovici, M. A. Prelas, M. McCormick, S. K. Loyalka, G. Manning, J. Farmer, H. W. White, and F. Shahedipour
Mat. Res. Soc. Proc. 416, 223 (1996)

Patent:

"Substrate Engineering Technique for Low dislocation Defect III-Nitride Wideband Gap Material (AlInGaN) Growth on Silicon Substrate,"
F. Shahedipour-Sandvik, Di Wu, and M. Jamil Khan, US pending patent, (2005)

Awards:

  • 2005, NY Governor's 2005 Women of Excellence Award
  • 2006, Rising to Lead "Best 2006 Technologist" awarded by Alliance for Technology and Women
  • 2007, "Women of Excellence in Emerging Professions", Albany-Colonie Chamber of Commerce
  • 2008, "25 Individuals who make a difference", Times Union, Albany, NY
  • 2009, nominated for "Blavatnik Award for Young Scientists", The New York Academy of Sciences