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1,084 results on '"Reddy, Pramod"'

2. Quantifying the Temperature of Heated Microdevices Using Scanning Thermal Probes

Author

Reihani, Amin, Yan, Shen, Luan, Yuxuan, Mittapally, Rohith, Meyhofer, Edgar, and Reddy, Pramod

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Quantifying the temperature of microdevices is critical for probing nanoscale energy transport.Such quantification is often accomplished by integrating resistance thermometers into microdevices. However, such thermometers frequently become structurally unstable and fail due to thermal stresses at elevated temperatures. Here, we show that custom-fabricated scanning thermal probes (STPs) with a sharp tip and an integrated heater/thermometer can accurately measure the temperature of microdevices held at elevated temperatures. This measurement is accomplished by introducing a modulated heat input to the STP after contacting the microdevice with the STP's tip, and characterizing the DC and AC components of the STP's temperature.From these measured temperature components, the tip-to-sample thermal resistance and the microdevice surface temperature are deduced via a simple lumped-capacitance model. The advances presented here can greatly facilitate temperature measurements of a variety of heated microdevices., Comment: Manuscript submitted to Applied Physics Letters

Published
2021
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10. Anderson transition in compositionally graded p-AlGaN.

Author

Rathkanthiwar, Shashwat, Reddy, Pramod, Quiñones, Cristyan E., Loveless, James, Kamiyama, Masahiro, Bagheri, Pegah, Khachariya, Dolar, Eldred, Tim, Moody, Baxter, Mita, Seiji, Kirste, Ronny, Collazo, Ramón, and Sitar, Zlatko

Subjects
*CONDUCTION bands, *POINT defects, *METAL-insulator transitions
Abstract

Mg-doped, graded AlGaN films showed the formation of an impurity band and high, temperature-invariant p-conductivity even for doping levels well below the Mott transition. However, compensating point defects disrupted the impurity band, resulting in an Anderson transition from the impurity band to valence band conduction and a more than tenfold reduction in room-temperature conductivity. This is the first demonstration of Anderson-like localization in AlGaN films. [ABSTRACT FROM AUTHOR]

Published
2023
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11. A Survey on Recent Deep Learning Architectures

Author

Bhargavi, G., Vaijayanthi, S., Arunnehru, J., Reddy, Pramod Reddy Devi, Kacprzyk, Janusz, Series Editor, Manoharan, Kalaiselvi Geetha, editor, Nehru, Jawaharlal Arun, editor, and Balasubramanian, Sivaraman, editor

Published
2021
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23. Heat dissipation in atomic-scale junctions

Author

Lee, Woochul, Kim, Kyeongtae, Jeong, Wonho, Zotti, Linda Angela, Pauly, Fabian, Cuevas, Juan Carlos, and Reddy, Pramod

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Atomic and single-molecule junctions represent the ultimate limit to the miniaturization of electrical circuits. They are also ideal platforms to test quantum transport theories that are required to describe charge and energy transfer in novel functional nanodevices. Recent work has successfully probed electric and thermoelectric phenomena in atomic-scale junctions. However, heat dissipation and transport in atomic-scale devices remain poorly characterized due to experimental challenges. Here, using custom-fabricated scanning probes with integrated nanoscale thermocouples, we show that heat dissipation in the electrodes of molecular junctions, whose transmission characteristics are strongly dependent on energy, is asymmetric, i.e. unequal and dependent on both the bias polarity and the identity of majority charge carriers (electrons vs. holes). In contrast, atomic junctions whose transmission characteristics show weak energy dependence do not exhibit appreciable asymmetry. Our results unambiguously relate the electronic transmission characteristics of atomic-scale junctions to their heat dissipation properties establishing a framework for understanding heat dissipation in a range of mesoscopic systems where transport is elastic. We anticipate that the techniques established here will enable the study of Peltier effects at the atomic scale, a field that has been barely explored experimentally despite interesting theoretical predictions. Furthermore, the experimental advances described here are also expected to enable the study of heat transport in atomic and molecular junctions, which is an important and challenging scientific and technological goal that has remained elusive., Comment: supporting information available in the journal web site or upon request

Published
2013
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24. Heat dissipation and its relation to thermopower in single-molecule junctions

Author

Zotti, Linda Angela, Bürkle, Marius, Pauly, Fabian, Lee, Woochul, Kim, Kyeongtae, Jeong, Wonho, Asai, Yoshihiro, Reddy, Pramod, and Cuevas, Juan Carlos

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Motivated by recent experiments [Lee et al. Nature 498, 209 (2013)], we present here a detailed theoretical analysis of the Joule heating in current-carrying single-molecule junctions. By combining the Landauer approach for quantum transport with ab initio calculations, we show how the heating in the electrodes of a molecular junction is determined by its electronic structure. In particular, we show that in general the heat is not equally dissipated in both electrodes of the junction and it depends on the bias polarity (or equivalently on the current direction). These heating asymmetries are intimately related to the thermopower of the junction as both these quantities are governed by very similar principles. We illustrate these ideas by analyzing single-molecule junctions based on benzene derivatives with different anchoring groups. The close relation between heat dissipation and thermopower provides general strategies for exploring fundamental phenomena such as the Peltier effect or the impact of quantum interference effects on the Joule heating of molecular transport junctions., Comment: 26 pages, 9 figures, submitted to New Journal of Physics

Published
2013
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25. High electron mobility in AlN:Si by point and extended defect management.

Author

Bagheri, Pegah, Quiñones-Garcia, Cristyan, Khachariya, Dolar, Rathkanthiwar, Shashwat, Reddy, Pramod, Kirste, Ronny, Mita, Seiji, Tweedie, James, Collazo, Ramón, and Sitar, Zlatko

Subjects
ELECTRON mobility, POINT defects, DISLOCATION density, COMPENSATION management, FERMI level, CHARGE carrier mobility
Abstract

High room temperature n-type mobility, exceeding 300 cm2/Vs, was demonstrated in Si-doped AlN. Dislocations and CN−1 were identified as the main compensators for AlN grown on sapphire and AlN single crystalline substrates, respectively, limiting the lower doping limit and mobility. Once the dislocation density was reduced by the growth on AlN wafers, C-related compensation could be reduced by controlling the process supersaturation and Fermi level during growth. While the growth on sapphire substrates supported only high doping ([Si] > 5 × 1018 cm−3) and low mobility (∼20 cm2/Vs), growth on AlN with proper compensation management enabled controlled doping at two orders of magnitude lower dopant concentrations. This work is of crucial technological importance because it enables the growth of drift layers for AlN-based power devices. [ABSTRACT FROM AUTHOR]

Published
2022
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32. Comparison of Efficacy and Safety of a Bevacizumab Biosimilar, in Combination with Chemotherapies, in Nonresectable Metastatic Colorectal Cancer and in Advanced Nonsquamous Non–Small Cell Lung Cancer: A Randomized, Double-Blind, Phase III Study

Author

Kasliwal, Shalu, additional, K., Ranjith, additional, Reddy, Pramod, additional, Maharaj, Narendra, additional, M., Gopichand, additional, Adhav, Aditya, additional, Harsh, Kamlesh, additional, Madnoorkar, Nagesh, additional, Diwan, Ashok, additional, Gupta, Mamraj, additional, Patel, Ghanshyam, additional, J., Srinivas B., additional, and Dvorkin, Mikhail Vladimirovich, additional

Published
2023
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44. GaN lateral polar junction arrays with 3D control of doping by supersaturation modulated growth: A path toward III-nitride superjunctions.

Author

Szymanski, Dennis, Khachariya, Dolar, Eldred, Tim B., Bagheri, Pegah, Washiyama, Shun, Chang, Alexander, Pavlidis, Spyridon, Kirste, Ronny, Reddy, Pramod, Kohn, Erhard, Lauhon, Lincoln, Collazo, Ramon, and Sitar, Zlatko

Subjects
ATOM-probe tomography, GALLIUM nitride, SUPERSATURATION, MASS spectrometry, CAPACITANCE measurement, CRYSTAL growth
Abstract

We demonstrate a pathway employing crystal polarity controlled asymmetric impurity incorporation in the wide bandgap nitride material system to enable 3D doping control during the crystal growth process. The pathway involves polarity specific supersaturation modulated growth of lateral polar structures of alternating Ga- and N-polar GaN domains. A STEM technique of integrated differential phase contrast is used to image the atomic structure of the different polar domains and their single atomic plane boundaries. As a demonstration, 1 μm wide alternating Ga- and N-polar GaN domains exhibiting charge balanced and periodic domains for superjunction technology were grown. The challenges in characterizing the resulting 3D doping profile were addressed with atom probe tomography with atomic scale compositional resolution corroborating capacitance measurements and secondary-ion mass spectroscopy analysis. [ABSTRACT FROM AUTHOR]

Published
2022
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45. Comparison of Efficacy and Safety of a Bevacizumab Biosimilar, in Combination with Chemotherapies, in Nonresectable Metastatic Colorectal Cancer and in Advanced Nonsquamous Non–Small Cell Lung Cancer: A Randomized, Double-Blind, Phase III Study.

Author

Kasliwal, Shalu, K., Ranjith, Reddy, Pramod, Maharaj, Narendra, M., Gopichand, Adhav, Aditya, Harsh, Kamlesh, Madnoorkar, Nagesh, Diwan, Ashok, Gupta, Mamraj, Patel, Ghanshyam, J., Srinivas B., and Dvorkin, Mikhail Vladimirovich

Published
2024
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