Heterostructures (HS) have always been in attraction due to their inherited properties and different important applications. integration of a phase-change material (pcM) with HS can tremendously extend the operating and application range using the "phase-tuning" of pcM for any optoelectronic devices. in the present study, we report a detailed study of electrical and optoelectronic characteristics of a p-p and p-n HS combining Ge 2 Sb 2 te 5 (GST) and Si. Reasonable 2 order of resistance switching is achieved by thermal annealing. the changes in optical properties are analysed using ellipsometry, UV-Vis-niR and Raman spectroscopy to speculate the optoelectronic behaviour of GSt/Si samples. the optical and electrical characterization were analysed with aluminium (Al), platinum (pt) and ti/ Au contacts. Appreciable rectifications varying from 500 to 1,000 at lower voltages are achieved with different contacts for both phases of GST. The change in rectification amount and current polarity are obtained with different kinds of contacts and at different incident wavelengths indicating different mechanisms of charge separation and collection. Responsivity of more than 9 A/W with < 1,000 photocurrent to dark-current ratio is demonstrated in wavelength range of 0.8-2 μm under moderate range of biasing under ~ μW source power illumination. The characteristics obtained were justified with the prediction of band alignment with the help of work-function difference measurement by Kelvinprobe force microscopy and carrier density measurement by Hall experiment. our results provide understanding to the opto-electrical behaviour of a heterojunction made of stacking PCM (GST) on Si highlighting their future use in photonic/optoelectronic-integrated circuits. Heterostructures have received intensive attentions due to their excellent intrinsic properties and wide applications ever since their emergence at very dawn of semiconductor (SC) technology in 1932 1. Heterostructures (HS), especially heterojunctions, juxtapose two different layers of materials which usually are of different materials having different properties. If the two materials are of same type (n-n or p-p) then it is called as "isotype" otherwise known as "anisotype" (e.g. n-p type) 2. Both types of the HS have their different potential applications 3. Fundamentally, instead of controlling the electrical parameters of a semiconductor by external doping and carrier injection, heterostructures can inherit different material properties of two layers e.g. controlling the charge transfer at the interface and controlling the fundamental parameters such as bandgap, effective masses, mobilities, refractive indices, etc., in the semiconductor based devices 4. Nowadays, scientists/researchers are more interested in the interactions at the junction interface to improve the performance and sometimes synergistic properties as well 5. HS are widely used as the basic building blocks in conventional devices such as photodiodes 6 , solar cells 7 , LEDs 8 , as well as in complicated struc...
We demonstrate functional switching of Electromagnetic Induced Transparency (EIT) in terahertz metasurface. We first simulated and fabricated two metasurfaces that have light difference in their unit cell design. Terahertz time domain spectroscopy (THz-TDS) of fabricated metasurfaces shows that two metasurfaces have almost similar transmission spectra but one of them possesses EIT while the second does not. To implement functional switching of EIT, we show numerically that characteristics of both metasurfaces can be achieved by a single hybrid metasurface containing a phase change material, Ge2Sb2Te5 (GST). GST has a large contrast in THz material properties in its crystalline and amorphous phases and its phase can be rapidly interchanged by external stimuli. We incorporated GST in the unit cell and show that phase change of GST portion in the metasurface unit cell at a specific location modulates the transmission spectra working as an EIT switch. EIT in the metasurface is attributed to coupling of two opposite phases bright resonance modes supported by the unit cell. The group delay of the transmitted THz radiation indicates that THz wave slows down significantly at EIT frequency. The dynamic interplay between two different responses within a single hybrid metasurface can have applications in biosensors, THz buffers, modulators, and other functional THz communication devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.