Effect of defect-induced cooling on graphene hot-electron bolometers
| Autor: | Rachael L. Myers-Ward, Yigit Aytac, Nicholas Quirk, Shojan P. Pavunny, Paola Barbara, Peize Han, Thomas E. Murphy, Kevin M. Daniels, D. Kurt Gaskill, Luke St. Marie, Abdel El Fatimy, Matthew T. Dejarld |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Graphene Phonon Mean free path FOS: Physical sciences 02 engineering and technology General Chemistry Electron 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Responsivity Thermal conductivity law Quantum dot Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Electron temperature General Materials Science 0210 nano-technology |
| Zdroj: | Carbon. 154:497-502 |
| ISSN: | 0008-6223 |
| Popis: | At high phonon temperature, defect-mediated electron-phonon collisions (supercollisions) in graphene allow for larger energy transfer and faster cooling of hot electrons than the normal, momentum-conserving electron-phonon collisions. Disorder also affects the heat flow between electrons and phonons at very low phonon temperature, where the phonon wavelength exceeds the mean free path. In both cases, the cooling rate is predicted to exhibit a characteristic cubic power law dependence on the electron temperature, markedly different from the T^4 dependence predicted for pristine graphene. The impact of defect-induced cooling on the performance of optoelectronic devices is still largely unexplored. Here we study the cooling mechanism of hot-electron bolometers based on epitaxial graphene quantum dots where the defect density can be controlled with the fabrication process. The devices with high defect density exhibit the cubic power law. Defect-induced cooling yields a slower increase of the thermal conductance with increasing temperature, thereby greatly enhancing the device responsivity compared to devices with lower defect density and operating with normal-collision cooling. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect