Wow this short video has so much information! and it's really cool to see that exciton physics being so robust even against abrasion. What is the reason for using polycarbonate instead of other polymers? What happens if you don't laminate the sample? do you see the films degrade? Can the laminating machine be used inside a glovebox to protect air sensitive flakes like CrI3? how does it compare to hBN encapsulation? is it air tight? What is the difference between the spectrometer you used vs the big and expensive ones?
Thanks! We've tried with polypropylene, mylar, PET and one can get similar results. We like polycarbonate results more because our provider gave us very flat one. Lamination is only advised in the experiment to avoid students to accidentally touch the films or scratch them. But they are very stable in time. Lamination inside the glovebox could be done and I believe that it's airtight. This is a completely different approach with respect to hBN encapsulation. Here one wants to encapsulate a large area, not possible to do with exfoliated hBN
Regarding spectrometer, compact CCD ones are much cheaper, of course. This experiment is a proposal for teaching labs (we assume that have limited access to instrumentation)
@@STRENGTHNANO Thank you so much for the quick reply. Many air sensitive materials tend to degrade even after hBN encapsulation if you leave the sample in ambient conditions. I think lamination could be a nice option for optical measurements of air sensitive materials. I guess it would be difficult to do for transport measurements. Hmm..perhaps one could invent a vacuum IC packaging setup to be operated inside the glovebox?
@@PhysicistMartin. For high quality optical measurements I guess that one should develop a high optical grade lamination pouch (not just buying in Office Depot). But seems feasible. Regarding the electrical transport, not impossible. We've laminated thin wired in the past and worked out ok. One could even go further evaporating thin metal tracks on the lamination pouch before encapsulating
The experiment uses powder of van der Waals semiconductors (MoS2, WS2, MoSe2, WSe2). They are similar to graphene structurally but very different from the electronic point of view
@@bring-it-on we have characterized the thickness variability in more detail here: www.nature.com/articles/s41528-022-00157-9 (see the Supp Info). For WS2 we see variation in thickness from 20nm to 60nm. Good enough to perform these transmission experiments and see the excitonic features
Wow this short video has so much information! and it's really cool to see that exciton physics being so robust even against abrasion.
What is the reason for using polycarbonate instead of other polymers?
What happens if you don't laminate the sample? do you see the films degrade?
Can the laminating machine be used inside a glovebox to protect air sensitive flakes like CrI3? how does it compare to hBN encapsulation? is it air tight?
What is the difference between the spectrometer you used vs the big and expensive ones?
Thanks! We've tried with polypropylene, mylar, PET and one can get similar results. We like polycarbonate results more because our provider gave us very flat one. Lamination is only advised in the experiment to avoid students to accidentally touch the films or scratch them. But they are very stable in time. Lamination inside the glovebox could be done and I believe that it's airtight. This is a completely different approach with respect to hBN encapsulation. Here one wants to encapsulate a large area, not possible to do with exfoliated hBN
Regarding spectrometer, compact CCD ones are much cheaper, of course. This experiment is a proposal for teaching labs (we assume that have limited access to instrumentation)
@@STRENGTHNANO Thank you so much for the quick reply.
Many air sensitive materials tend to degrade even after hBN encapsulation if you leave the sample in ambient conditions. I think lamination could be a nice option for optical measurements of air sensitive materials. I guess it would be difficult to do for transport measurements. Hmm..perhaps one could invent a vacuum IC packaging setup to be operated inside the glovebox?
@@PhysicistMartin. For high quality optical measurements I guess that one should develop a high optical grade lamination pouch (not just buying in Office Depot). But seems feasible. Regarding the electrical transport, not impossible. We've laminated thin wired in the past and worked out ok. One could even go further evaporating thin metal tracks on the lamination pouch before encapsulating
@@STRENGTHNANO wow that's incredible
What is this small material all about ? Is this graphene
The experiment uses powder of van der Waals semiconductors (MoS2, WS2, MoSe2, WSe2). They are similar to graphene structurally but very different from the electronic point of view
@@STRENGTHNANO have you mixed them all together or this particular one
@@bring-it-on, it's one material at a time.
@@STRENGTHNANO Thanks for your quick respond.using cotton stick to creat thin layer I agree but uniformity is questionable...
@@bring-it-on we have characterized the thickness variability in more detail here: www.nature.com/articles/s41528-022-00157-9 (see the Supp Info). For WS2 we see variation in thickness from 20nm to 60nm. Good enough to perform these transmission experiments and see the excitonic features