Novel synthesis and design methods of optical thin film structures using vanadium dioxide phase change material

Author(s):  
Andrew M. Sarangan
Author(s):  
Muhammad Fayyaz Kashif ◽  
Tiziana Stomeo ◽  
Francesco Guido ◽  
Maria A. Vincenti ◽  
Irene Vassalini ◽  
...  

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Seung-Yeol Lee ◽  
Yong-Hae Kim ◽  
Seong-M. Cho ◽  
Gi Heon Kim ◽  
Tae-Youb Kim ◽  
...  

Author(s):  
Crunteanu Aurelian ◽  
VK Thalakkatukalathil Vinod ◽  
Orlianges Jean-Christophe ◽  
Bessaudou Annie

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Qilong Cheng ◽  
Sukumar Rajauria ◽  
Erhard Schreck ◽  
Robert Smith ◽  
Na Wang ◽  
...  

AbstractThe microelectronics industry is pushing the fundamental limit on the physical size of individual elements to produce faster and more powerful integrated chips. These chips have nanoscale features that dissipate power resulting in nanoscale hotspots leading to device failures. To understand the reliability impact of the hotspots, the device needs to be tested under the actual operating conditions. Therefore, the development of high-resolution thermometry techniques is required to understand the heat dissipation processes during the device operation. Recently, several thermometry techniques have been proposed, such as radiation thermometry, thermocouple based contact thermometry, scanning thermal microscopy, scanning transmission electron microscopy and transition based threshold thermometers. However, most of these techniques have limitations including the need for extensive calibration, perturbation of the actual device temperature, low throughput, and the use of ultra-high vacuum. Here, we present a facile technique, which uses a thin film contact thermometer based on the phase change material $$Ge_2 Sb_2 Te_5$$ G e 2 S b 2 T e 5 , to precisely map thermal contours from the nanoscale to the microscale. $$Ge_2 Sb_2 Te_5$$ G e 2 S b 2 T e 5 undergoes a crystalline transition at $$\hbox {T}_{{g}}$$ T g with large changes in its electric conductivity, optical reflectivity and density. Using this approach, we map the surface temperature of a nanowire and an embedded micro-heater on the same chip where the scales of the temperature contours differ by three orders of magnitude. The spatial resolution can be as high as 20 nanometers thanks to the continuous nature of the thin film.


Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hassan Divdel ◽  
Hamed Taghipour-Farshi ◽  
Hassan Rasooli Saghai ◽  
Mohammad-Ali Tavakoli Ghazi Jahani

Abstract A terahertz metasurface absorber with actively switchable bandwidth enabled by vanadium dioxide (VO2) is presented and investigated numerically. The VO2 is a phase-change material and its conductivity in the terahertz range changes by several orders of magnitude upon phase-transition. The metasurface consists of an H-shaped fractal resonator placed on top of a polyimide spacer and a ground-plane of gold. The resonator is composed of an H-shaped level-1 fractal of gold and VO2 strips that converts it to a level-2 fractal. At room temperatures, the VO2 is in the insulator state and the resonator reduces to a level-1 fractal offering narrowband absorption at 8.08 THz reaching 0.98 absorption. At higher temperatures, the VO2 is in the metallic state and the resonator is effectively a level-2 fractal with an absorption higher than 0.9 in a bandwidth of 6.63–9.89 THz.


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