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Selected Works

2015

Guru Subramanyam

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Articles 31 - 34 of 34

Full-Text Articles in Engineering

Performance Of Thin Film Ferroelectrics With Dopant-Ion Charges, Huadong Li, Guru Subramanyam, Jiadong Wang Mar 2015

Performance Of Thin Film Ferroelectrics With Dopant-Ion Charges, Huadong Li, Guru Subramanyam, Jiadong Wang

Guru Subramanyam

This paper studied the effect of dopant-ion charges on the performance of thin film ferroelectrics. Field distributions and capacitance of ferroelectric thin films with different dopant-ion charge densities are analyzed. The non-linearity of the electric field inside the thin film increases with the dopant-ion charge density and decreases with the linear permittivity of the ferroelectric thin film. Once the applied voltage is strong enough, the field distribution will become linear. The FE thin film peak capacitance reduces with the dopant-ion charge density and the total area under the C-V curve between two large voltages with opposite signs is fixed.


Voltage Tunable Epitaxial Pb X Sr(1− X )Tio3 Films On Sapphire By Mocvd: Nanostructure And Microwave Properties, S. Dey, C. Wang, W. Cao, S. Bhaskar, J. Li, Guru Subramanyam Mar 2015

Voltage Tunable Epitaxial Pb X Sr(1− X )Tio3 Films On Sapphire By Mocvd: Nanostructure And Microwave Properties, S. Dey, C. Wang, W. Cao, S. Bhaskar, J. Li, Guru Subramanyam

Guru Subramanyam

Frequency and phase agile microwave components such as tunable filters and phase shifters will require ferroelectric thin films that exhibit a nonlinear dependence of dielectric permittivity (ɛ r ) with dc electric bias, as well as a high material (Δɛ r /tan δ) and device (or K-factor in phase shift/dB) figure of merits (FOM). Therefore, voltage tunable (Pb0.3Sr0.7)TiO3 (PST) thin films (90–150 nm) on (0001) sapphire were deposited by metal-organic chemical vapor deposition at rates of 10–15 nm/min. The as-deposited epitaxial PST films were characterized by Rutherford backscattering spectroscopy, X-ray methods, field …


Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio-Frequency/Microwave Components, Guru Subramanyam, M W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M. Sbrockey, Gary S. Tompa, Xiaomei Guo, Chonglin Chen, S P. Alpay, G A. Rossetti Jr., Kaushik Dayal, Long-Qing Chen, Darrell G. Schlom Jan 2015

Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio-Frequency/Microwave Components, Guru Subramanyam, M W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M. Sbrockey, Gary S. Tompa, Xiaomei Guo, Chonglin Chen, S P. Alpay, G A. Rossetti Jr., Kaushik Dayal, Long-Qing Chen, Darrell G. Schlom

Guru Subramanyam

There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated …


Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio Frequency/Microwave Components, Guru Subramanyam, Melanie W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M. Sbrockey, Gary S. Tompa, Xiaomei Guo, Chonglin Chen, S. P. Alpay, G. A. Rossetti, Kaushik Dayal, Long-Qing Chen, Darrell Schlom Jan 2015

Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio Frequency/Microwave Components, Guru Subramanyam, Melanie W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M. Sbrockey, Gary S. Tompa, Xiaomei Guo, Chonglin Chen, S. P. Alpay, G. A. Rossetti, Kaushik Dayal, Long-Qing Chen, Darrell Schlom

Guru Subramanyam

There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated …