| 1. |
- Skoblin, Grigory, 1991, et al.
(författare)
-
A hybrid-type CVD system for graphene growth
- 2015
-
Ingår i: Chemical Vapor Deposition. - : Wiley. - 1521-3862 .- 0948-1907. ; 21:7-9, s. 176-180
-
Tidskriftsartikel (refereegranskat)abstract
- A cold-wall CVD system for graphene growth on metal foils is converted to an effectively hot-wall one by merely adding another heater, sandwiching the foil in between the heaters. This simple design demonstrates both an improved temperature uniformity characteristic for hot-wall systems, and a high responsivity distinctive for cold-wall ones. This beneficial combination allows for a much better control of graphene growth kinetics. An effectively hot-wall system for graphene growth is made from a cold-wall one by encapsulating the metal foil in between two heaters. This simple conversion demonstrates improved temperature control and high temperature ramping rate. It also allows reaching lower nucleation density and provides better control of growth kinetics.
|
|
| 2. |
- Skoblin, Grigory, 1991, et al.
(författare)
-
Encapsulation of graphene in Parylene
- 2017
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:5
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene encapsulated between flakes of hexagonal boron nitride (hBN) demonstrates the highest known mobility of charge carriers. However, the technology is not scalable to allow for arrays of devices. We are testing a potentially scalable technology for encapsulating graphene where we replace hBN with Parylene while still being able to make low-ohmic edge contacts. The resulting encapsulated devices show low parasitic doping and a robust Quantum Hall effect in relatively low magnetic fields
|
|
| 3. |
- Skoblin, Grigory, 1991, et al.
(författare)
-
Graphene bolometer with thermoelectric readout and capacitive coupling to an antenna
- 2018
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 112:6
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a prototype graphene radiation detector based on the thermoelectric effect. We used a split top gate to create a p-n junction in the graphene, thereby making an effective thermocouple to read out the electronic temperature in the graphene. The electronic temperature is increased due to the AC currents induced in the graphene from the incoming radiation, which is first received by an antenna and then directed to the graphene via the top-gate capacitance. With the exception of the constant DC voltages applied to the gate, the detector does not need any bias and is therefore very simple to use. The measurements showed a clear response to microwaves at 94 GHz with the signal being almost temperature independent in the 4-100 K temperature range. The optical responsivity reached ∼700 V/W.
|
|
| 4. |
- Skoblin, Grigory, 1991, et al.
(författare)
-
Thermoelectric effects in graphene at high bias current and under microwave irradiation
- 2017
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- We use a split top gate to induce doping of opposite signs in different parts of a graphene field-effect transistor, thereby effectively forming a graphene thermocouple. The thermocouple is sensitive to the electronic temperature in graphene, which can be several hundred kelvin higher than the ambient one at sufficiently high bias current. Combined with the high thermoelectric power of graphene, this allows for i) simple measurements of the electronic temperature and ii) building thermoelectric radiation detectors. A simple prototype graphene thermoelectric detector shows a temperature-independent optical responsivity of around 400 V/W at 94 GHz at temperatures of 4-50 K.
|
|
| 5. |
- Zhan, Zhaoyao, 1983, et al.
(författare)
-
Pore-free bubbling delamination of chemical vapor deposited graphene from copper foils
- 2015
-
Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7534 .- 2050-7526. ; 3:33, s. 8634-8641
-
Tidskriftsartikel (refereegranskat)abstract
- The electrolytic bubbling-assisted transfer of graphene from metal catalysts in chemical vapor deposition provides a high efficiency, low cost and environmental benign alternative to the traditional chemical etching method. Despite its high potential, the yield of bubbling delamination is yet low, mainly due to the induced pores in the graphene after the transfer. It is found that water and protons transported through the poly(methyl methacrylate) (PMMA) supporting layer play a critical role in pore formation. Once water and protons reach the PMMA-graphene interface before delamination is finished, the protons permeate the graphene and form trapped hydrogen bubbles between the graphene and the metal. The built-up gas pressure inside the bubbles is high enough to crack the PMMA/graphene sheet, thereby creating pores in the graphene. An optimized PMMA layer not only reduces trapped hydrogen bubble generation, but it is also mechanically stronger preventing cracking. This contributes significantly to the pore-free electrolytic bubbling-assisted delamination of graphene.
|
|
