Thermoelectric- and hot-electron effects in graphene devices
Doktorsavhandling, 2017
A technology of encapsulation of graphene in Parylene was introduced
as an alternative to encapsulating graphene in hBN. Edge contacts to the
encapsulated graphene in this case showed resistivity down to 14 Ohm um,
which is the lowest reported value so far. The resulting graphene devices
showed a high carrier mobility (up to 30000 cm2/(V s) at 300K), low doping
(down to 10^11 cm2) and were stable in time. Possibility of encapsulating
also CVD graphene for large-scale device fabrication was shown.
This Parylene encapsulation technology was used for fabrication of thermoelectric
graphene devices and radiation detectors. Since the Seebeck coef-
cient in graphene is high, the thermoelectric eects are strong. A dual-gated
design was used to create an intrinsic graphene thermocouple. Due to a weak
coupling between phonons and electrons in graphene, the electrons can have
signicantly higher temperature than the phonons. These devices allowed
for simple measurement of electron temperature in graphene. When coupled
to an antenna, such a device served as a radiation detector. Even under
unoptimized conditions the detectors showed responsivity up to 700 V/W
and noise level down to 18 pW/Hz^0.5. The response time was estimated to
be less than 1.2 ps.
Parylene
bolometer
CVD
encapsulation
graphene
thermoelectric effects
Kollektorn, Kemivägen 9, Chalmers
Opponent: Thomas Mueller, Vienna University of Technology, Austria
Författare
Grigory Skoblin
Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik
A hybrid-type CVD system for graphene growth
Chemical Vapor Deposition,; Vol. 21(2015)p. 176-180
Artikel i vetenskaplig tidskrift
Encapsulation of graphene in Parylene
Applied Physics Letters,; Vol. 110(2017)
Artikel i vetenskaplig tidskrift
Thermoelectric effects in graphene at high bias current and under microwave irradiation
Scientific Reports,; Vol. 7(2017)
Artikel i vetenskaplig tidskrift
Skoblin, G., Sun, J., Yurgens, A, Thermoelectric graphene bolometer with capacitive coupling to an antenna
This thesis is devoted to fabrication of graphene devices and investigation of thermoelectric effects in them.
Graphene is a wonderful material, which was discovered 10 years ago. It has very rich spectrum of properties, many of them can be very useful in various applications. Graphene became one of the hottest fields in modern physics.
The electronic properties of graphene can be easily affected by the ambient. In order to fabricate reliable graphene devices, it is beneficial to encapsulate it inside an insulator. The method to get the devices of highest quality relies on encapsulating graphene in hexagonal boron nitride. However, this method is very complicated and is not suitable for industrial applications.
In this work an alternative technology of graphene device fabrication is suggested - encapsulating in Parylene. This technology provides potential scalability, which would be very useful for industry. The quality of the fabricated devices is high enough for many applications. One of such applications is presented in this work: thermoelectric hot-electron bolometers are fabricated and investigated. These bolometers show the responsivity and noise level comparable to the other high-frequency detectors. The main advantages of our bolometers are the fast response time and the wide working temperature range - from room- down to cryogenic temperatures.
After further optimization, the presented thermoelectric bolometers can potentially be used for various applications.
Graphene is a wonderful material, which was discovered 10 years ago. It has very rich spectrum of properties, many of them can be very useful in various applications. Graphene became one of the hottest fields in modern physics.
The electronic properties of graphene can be easily affected by the ambient. In order to fabricate reliable graphene devices, it is beneficial to encapsulate it inside an insulator. The method to get the devices of highest quality relies on encapsulating graphene in hexagonal boron nitride. However, this method is very complicated and is not suitable for industrial applications.
In this work an alternative technology of graphene device fabrication is suggested - encapsulating in Parylene. This technology provides potential scalability, which would be very useful for industry. The quality of the fabricated devices is high enough for many applications. One of such applications is presented in this work: thermoelectric hot-electron bolometers are fabricated and investigated. These bolometers show the responsivity and noise level comparable to the other high-frequency detectors. The main advantages of our bolometers are the fast response time and the wide working temperature range - from room- down to cryogenic temperatures.
After further optimization, the presented thermoelectric bolometers can potentially be used for various applications.
Fundament
Grundläggande vetenskaper
Infrastruktur
Nanotekniklaboratoriet
Lärande och undervisning
Pedagogiskt arbete
Ämneskategorier
Annan elektroteknik och elektronik
Den kondenserade materiens fysik
ISBN
978-91-7597-681-5
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4362
Utgivare
Chalmers
Kollektorn, Kemivägen 9, Chalmers
Opponent: Thomas Mueller, Vienna University of Technology, Austria