Ultrawide Bandgap Semiconductor Laboratory
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Publications
1. Reduction in Density of Interface Traps Determined by C-V Analysis in III-nitride Based MOSHFET Structure., Samiul Hasan*, Mohi Uddin Jewel*, Scott R. Crittenden, Md Ghulam Zaki, Nifat Jahan Nipa, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, and Iftikhar Ahmad, Applied Physics Letters, 124, 112103, https://doi.org/10.1063/5.0193603 (2024).
2. Alpha Particle Detection Using Highly Rectifying Ni/Ga2O3/4H-SiC Heteroepitaxial MOS Junction, Sandeep K. Chaudhuri, Ritwik Nag, Iftikhar Ahmad, and Krishna C. Mandal, IEEE TRANSACTIONS ON ELECTRON DEVICES, 70 (12), doi.org/10.1109/TED.2023.3328329. (2023)
3. Phase Stabilized MOCVD Growth of β-Ga2O3 Using SiOx on c-Plane Sapphire and AlN/Sapphire Template, Mohi Uddin Jewel*, Samiul Hasan*, Scott R. Crittenden, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, Iftikhar Ahmad, Phys. Status Solidi A,220, 2300036, doi.org/10.1002/pssa.202300036. (2023).
4. MOCVD-grown β-Ga2O3 as a Gate Dielectric on AlGaN/GaN-Based Heterojunction Field Effect Transistor, Samiul Hasan*, Mohi Uddin Jewel*, Scott R. Crittenden, Dongkyu Lee, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, and Iftikhar Ahmad, Crystals, 13, 231. doi.org/10.3390/cryst13020231. (2023).
5. A comprehensive study of defects in gallium oxide by density functional theory, Mohi Uddin Jewel*, Samiul Hasan*, and Iftikhar Ahmad, Computational Materials Science 218, 111950, doi.org/10.1016/j.commatsci.2022.111950. (2023).
6. Progress in Hexagonal Boron Nitride (h-BN)-Based Solid-State Neutron Detector, Samiul Hassan*, and Iftikhar Ahmad, Electron. Mater., 3(3), 235-251, doi.org/10.3390/electronicmat3030020 (2022).
7. Comparative Spectroscopic Study of Aluminum Nitride Grown by MOCVD in H2 and N2 Reaction Environment, Samiul Hasan*, Mohi Uddin Jewel*, Stavros G. Karakalos, Mikhail Gaevski, and Iftikhar Ahmad, MDPI Journal – Special Issue "Thin Films and Nanostructures by MOCVD: Fabrication, Characterization and Applications" Coatings, 2022, 12(7), 924 (2022), doi.org/10.3390/coatings12070924 (2022).
8. Growth evolution of high-quality MOCVD aluminum nitride using nitrogen as carrier gas on the sapphire substrate, Samiul Hasan*, Abdullah Mamun, Kamal Hussain, Mikhail Gaevski, Iftikhar Ahmad & Asif Khan, Journal of Materials Research, vol. 36, pp. 4360–4369 (2021).
9. Investigation of MOCVD grown crack-free 4 μm thick aluminum nitride using nitrogen as a carrier gas, Samiul Hasan*, Abdullah Mamun, Kamal Hussain, Dhruvinkumar Patel, Mikhail Gaevski, Iftikhar Ahmad* & Asif Khan, Material Research Society Advances, vol. 6, pp. 456–460 (2021).
10. High-Temperature Operation of AlxGa1-xN (x > 0.4) Channel Metal Oxide Semiconductor Heterostructure Field Effect Transistors with High-k Atomic Layer Deposited Gate Oxides Shahab Mollah, Kamal Hussain, Richard Floyd, Abdullah Mamun, Mikhail Gaevski, MVS Chandrashekhar, Iftikhar Ahmad, Grigory Simin, and Hashem A. Fathallah, J. Appl. Phys. 125, 054501, doi.org/10.1063/1.5012730 (2022).
11. Ultra-wide bandgap AlGaN metal oxide semiconductor heterostructure field effect transistors with high-k ALD ZrO2 dielectric, Shahab Mollah, Mikhail Gaevski, MVS Chandrashekhar, Xuhong Hu, Virginia Wheeler, Kamal Hussain, Abdullah Mamun, Richard Floyd, Iftikhar Ahmad, Grigory Simin, Charles Eddy, and Asif Khan, Semicond. Sci. Technol. 34, 125001 (2019).
12. Deep ultraviolet photo pumped stimulated emission from partially relaxed AlGaN multiple quantum well heterostructures grown on sapphire substrates, Fatima Asif, Mohamed Lachab, Antwon Coleman, Iftikhar Ahmad, Bin Zhang; Vinod Adivarahan, Asif Khan, J. Vac. Sci. Technol. B 32, 061204 (2014).
13. Pseudomorphic Al xGa1-x N MQW based deep ultraviolet light emitting diodes over sapphire, Fatima Asif , Hung-Chi Chen, Antwon Coleman, Iftikhar Ahmad, Bin Zhang, Joe Dion , Ahmad Heidari, Vinod Adivarahan, and Asif Khan, Phys. Status Solidi C, 11, No. 3–4, 798 (2014).
14. Enhancement of light extraction efficiency in sub-300 nm nitride thin-film flip-chip light-emitting diodes, M. Lachab, F. Asif , B. Zhang , I. Ahmad, A. Heidari, Q. Fareed, V. Adivarahan, A. Khan, Solid-State Electronics, 89, 156 (2013).
15. Substrate Lifted-off AlGaN/AlGaN Lateral Conduction Thin-Film Light-Emitting Diodes Operating at 285 nm, Fatima Asif, Hung-Chi Chen, Antwon Coleman, Mohamed Lachab, Iftikhar Ahmad, Bin Zhang, Qhalid Fareed, Vinod Adivarahan and Asif Khan, Jpn. J. Appl. Phys. 52, 08JG14, (2013).
16. MOCVD growth of semipolar Al{sub x}Ga{sub 1-x}N on m-plane sapphire for applications in deep-ultraviolet light emitters, K. Balakrishnan, M. Lachab, H. C. Chen, D. Blom, V. Adivarahan, I. Ahmad, Q. Fareed, M. A. Khan, Phys. Status Solidi A 208, No. 12, 2724–2729 (2011).
17. 276 nm Substrate-Free Flip-Chip AlGaN Light-Emitting Diodes, Seongmo Hwang, Daniel Morgan, Amanda Kesler, Mohamed Lachab, Bin Zhang, Ahmad Heidari, Haseeb Nazir, Iftikhar Ahmad, Joe Dion, Qhalid Fareed, Vinod Adivarahan, Monirul Islam, and Asif Khan, Appl. Phys. Express 4, 032102 (2011).
18. Dislocation reduction in high Al-content AlGaN films for deep ultraviolet light emitting diodes, Iftikhar Ahmad, Balakrishnan Krishnan, Bin Zhang, Qhalid Fareed, Mohamed Lachab, Joseph Dion, Asif Khan, Phys. Status Solidi A 208, No. 7 (2011).
19. Effect of Temperature on the Growth of InAs/GaAs Quantum Dots Grown on a Strained GaAs Layer, Ahmad I., Avrutin V.; Morkoç H., Moore J. C., Baski, A. A., Journal of Nanoscience and Nanotechnology, Volume 7, Number 8 (2007).
20. Self-heating in a GaN based heterostructure field effect transistor: Ultraviolet and visible Raman measurements and simulations, I. Ahmad, V. Kasisomayajula, D. Y. Song, L. Tian, J. M. Berg, M. Holtz, J. Appl. Phys. 100, 113718 (2006).
21. Depth dependence of defect density and stress in GaN grown on SiC, N. Faleev, H. Temkin; I. Ahmad, M. Holtz, Yu. Melnik, J. Appl. Phys. 98, 123508 (2005).
22. Self-heating study of an AlGaN/GaN based heterostructure field-effect transistor using ultraviolet micro-Raman scattering, I. Ahmad, V. Kasisomayajula, and M. Holtz, J. M. Berg, S. R. Kurtz, C. P. Tigges, A. A. Allerman, and A. G. Baca, Appl. Phys. Lett. 86, 173503 (2005).
23. Controlled growth of GaN nanowires by pulsed metalorganic chemical vapor deposition, G. Kipshidze,a! B. Yavich, A. Chandolu, J. Yun, V. Kuryatkov, I. Ahmad, D. Aurongzeb, M. Holtz, and H. Temkin, Appl. Phys. Lett. 86, 033104 (2005).
24. Optical properties of a nanoporous array in silicon, L. Tian, K. Bhargava Ram, I. Ahmad, L. Menon, and M. Holtz, J. Appl. Phys. 97, 026101 (2005).
25. Dependence of the stress–temperature coefficient on dislocation density in epitaxial GaN grown on a-Al2O3 and 6H–SiC substrates, I. Ahmad and M. Holtz, N. N. Faleev, and H. Temkin, J. Appl. Phys., 95, 4, (2004).
26. Deep Ultraviolet Light Emitting Diodes Based on Short Period Superlattices of AlN/AlGa(In)N, Sergey A. NIKISHIN, Vladimir V. KURYATKOV, Anilkumar CHANDOLU, Boris A. BORISOV, Gela D. KIPSHIDZE, Iftikhar AHMAD, Mark HOLTZ, and Henryk TEMKIN, Jpn. J. Appl. Phys., 42, L 1362–L 1365 (2003).
27. Microfabrication and Characterization of Teflon AF-Coated Liquid Core Waveguide Channels in Silicon, Arindom Datta, In-Yong Eom, Achintya Dhar, Petr Kuban, Rosalynn Manor, Iftikhar Ahmad, Shubhra Gangopadhyay, Tim Dallas, Mark Holtz, Henryk Temkin, IEEE SENSORS JOURNAL, 3, 6, (2003).
Refereed Conference Papers
1. Demonstration of thick phase-pure β-Ga2O3 on a c-plane sapphire substrate using MOCVD, Proc. SPIE 12422, Oxide-based Materials and Devices, Mohi Uddin Jewel*, Samiul Hasan*, Scott R. Crittenden, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, Iftikhar Ahmad, Proc. SPIE 12421, Proc. SPIE 12421, Gallium Nitride Materials and Devices XIV, 1242204, doi.org/10.1117/12.2661097 (2023).
2. Gate leakage current and threshold voltage characteristics of β-Ga2O3 passivated AlGaN/GaN based heterojunction field effect transistor, Samiul Hasan*, Mohi Uddin Jewel*, Scott R. Crittenden, Dongkyu Lee, Vitaliy S. Avrutin, Ümit Özgür, Hadis Morkoç, and Iftikhar Ahmad. Proc. SPIE 12421, Gallium Nitride Materials and Devices XVIII, 124210A, doi.org/10.1117/12.2668236 (2023).
Abstracts
1. Electrical properties of AlGaN/GaN based heterojunction field effect transistor structures with a β-Ga2O3 gate dielectric grown by MOCVD, Samiul Hasan*, Mohi Uddin Jewel*, Scott R. Crittenden, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, and Iftikhar Ahmad Photonics West, January 2023.
2 .Phase Stabilized MOCVD Growth of Phase-Pure β-Ga2O3 on c-Plane Sapphire, Mohi Uddin Jewel*, Samiul Hasan*, Scott R. Crittenden, Vitaliy Avrutin, Ümit Özgür, Hadis Morkoç, and Iftikhar Ahmad, SPIE Photonics West, January 2023.
3. Comparative Spectroscopic Study of AlN Grown by MOCVD in H2 and N2 Reaction Environment, Samiul Hasan*, Mohi Uddin Jewel*, Stavros Karakolos, Mikhael Gaevski, and Iftikhar Ahmad, Control ID 3676535, MRS 2022 – Online oral presentation.
4. Ultraviolet Light Emitting Diodes (U-LEDs), Samiul Hassan*, Jewel Mohiuddin* – Mentored by Iftikhar Ahmad – Discover UofSC, April 2022.
5. Native Point Defects in Gallium Oxide Material - Jewel Mohiddin*, Samiul Hassan*, Mentored by Iftikhar Ahmad– Discover UofSC, April 2022.
6. Comparative spectroscopic study of Aluminum Nitride grown by MOCVD in Hydrogen and Nitrogen reaction environment, Samiul Hasan*, Jewel Mohiuddin*, Stavros G. Karakalos, Mikhail Gaevski, and Iftikhar Ahmad, 22 MRS spring meeting 2022.
7. Growth of High Quality MOCVD Aluminum Nitride Using N2 as Carrier Gas, Samiul Hasan*, Abdullah Mamun, Kamal Hussain, Dhruvinkumar Patel, Mikhail Gaevski, Iftikhar Ahmad and Asif Khan, presented at the Virtual Material Research Society Spring Meeting & Exhibit, (2021).
8. Thick AlN Templates By MOCVD for the Thermal Management of III-N Electronics A. Mamun, K. Hussain, M. U. Jewel, S. Mollah, K. Huynh, M. E. Liao, T. Bai, Y. R. Koh, Z. Cheng, M. S. B. Hoque, L. Yates, J. Gaskins, J. Tomko, I. Ahmad, M. Gaevski, M. Chandrashekhar, G. Simin, M. S. Goorsky, S. Graham, P. Hopkins, and A. Khan, 239th ECS meeting (May 30-June 3, 2021).
9. Crack and Strain Free 16 µm thick AlN on Sapphire templates, M. Mamun, Kamal Hussain, A. Iftikhar, M. Gaevski, MVS. Chandrashekhar, Kenny Huynh, Michael Liao, Tingyu Bai, M. Goorsky, G. Simin and Asif Khan, 13th International Conference on Nitride Semiconductor 2019 (ICNS-13), Bellevue, WA, July 07-12, 2019.
10. Recent advances in III-Nitride devices using ultrawide bandgap AlxGa1-xN Active layers Mikhail Gaevski, Shahab Mollah, Kamal Hussain, Richard Floyd, Abdullah Mamun, MVS Chandrashekhar, Iftikhar Ahmad, Grigory Simin, Virginia Wheeler, Charles Eddy, and Asif Khan, 236th ECS Meeting, October 13-17, 2019, | Atlanta, GA. (INVITED).
11. Mikhail Gaevski, Shahab Mollah, Kamal Hussain, Richard Floyd, Abdullah Mamun, MVS Chandrashekhar, Iftikhar Ahmad, Grigory Simin, Virginia Wheeler, Charles Eddy and Asif Khan, "Dynamic Performance of AlGaN MOSHFETs with high-k ALD oxides", 13th International Conference on Nitride Semiconductor 2019 (ICNS-13), Bellevue, WA, July 07-12, 2019.
12. AlxGa1-xN (x>0.4) Channel MOSHFETs with high-k ALD gate-oxides, Shahab Mollah, Kamal Hussain, Richard Floyd, Abdullah Mamun, Mikhail Gaevski, MVS Chandrashekhar, Iftikhar Ahmad, Grigory Simin, Virginia Wheeler, Charles Eddy and Asif Khan, , 13th International Conference on Nitride Semiconductor 2019 (ICNS-13), Bellevue, WA, July 07-12, 2019.
13. Solar Blind High-k ZrO¬¬2¬ Gate AlGaN MOSHFET Photodetector, Mohi Uddin Jewel, Md. Didarul Alam, Shahab Mollah, Richard Floyd, Kamal Hussain, Mikhail Gaevski, Iftikhar Ahmad, Grigory Simin, Asif Khan, and MVS Chandrashekhar, 13th International Conference on Nitride Semiconductor 2019 (ICNS-13), Bellevue, WA, July 07-12, 2019.
14. AlGaN MOSHFETs with high-k ALD oxides, Shahab Mollah, Richard Floyd, Kamal Hussain, Mikhail Gaevski, Iftikhar Ahmad, MVS Chandrashekhar, Grigory Simin, Virginia Wheeler, Charles Eddy and Asif Khan, 61st Electronic Materials Conference (EMC) 2019, Ann Arbor, MI, June 26- 28, 2019.
Presentations
1. Self-heating study of an AlGaN/GaN-based high electron mobility transistor using visible and ultraviolet micro-Raman scattering, I. Ahmad, V. Kasisomayajula, J.M. Berg, M. Holtz, S.R. Kurtz, C.P. Tigges, A.A. Allerman, A.G. Baca, APS March Meeting, Abstract ID: BAPS.2005.MAR.N18.7 (2005).
2. A correlated Raman and X-ray diffraction study of GaN and AlN grown on sapphire and silicon carbide substrates: Micro-Raman imaging and reciprocal space maps, I. Ahmad, Holtz, M., Faleev, N., Kipshidze, G., Temkin, H., APS March Meeting, - abstract id. Z23.003 (2003).
Scholarly Exhibits or Performances in the Arts
1. Study of Indium-Silicon Co-doped Gallium Oxide for Effective n-type Doping, Muhammad Hassan Tahir*, supervisor: Iftikhar Ahmad, Discover USC 2024.
2. Gallium Oxide-based Avalanche Photodetector, Md. Ghulam Zakir*, Supervisor: Iftikhar Ahmad, Discover 2024.
3. Study of Interface Charges Between In-situ Grown Dielectric and GaN/AlGaN HFET Structure by Metal-organic Chemical Vapor Deposition, Nifat Jahan Nipa*, Supervisor: Iftikhar Ahmad, Discover USC 2024.
4. Ultrawide Bandgap Semiconductor Materials Growth and Characterization Capabilities. Kiyona* Trevino*, Tyrese Smally (undergraduate students for summer) – Guided by Iftikhar Ahmad.
5. Boron Aluminum Nitride: A new material for superior performance of III-Nitride UV- LED. (Poster), Samiul Hasan*, Iftikhar Ahmad, Discover UofSC, April 23, 2021.
6. Low temperature study of micro pixel ultraviolet light emitting diode (Micro-DUV LEDs), Dhruvinkumar Patel* and Iftikhar Ahmad, (Poster) Discover UofSC, April 23, 2021.