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 (MC2), 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.

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 tekniska högskola

Kollektorn, Kemivägen 9, Chalmers

Opponent: Thomas Mueller, Vienna University of Technology, Austria

Mer information

Skapat

2017-12-22