Position dependent photodetector from large area reduced graphene oxide thin films

Abstract

We fabricated large area infrared photodetector devices from thin film of chemically reduced graphene oxide (RGO) sheets and studied their photoresponse as a function of laser position. We found that the photocurrent either increases, decreases or remain almost zero depending upon the position of the laser spot with respect to the electrodes. The position sensitive photoresponse is explained by Schottky barrier modulation at the RGO film-electrode interface. The time response of the photocurrent is dramatically slower than single sheet of graphene possibly due to disorder from the chemically synthesis and interconnecting sheets.

Coulomb blockade and hopping conduction in graphene quantum dots array

“…The graphitic regions were estimated to be of 3-10 nm from the TEM, STM and Raman studies [11][12][13][14][15]. Optical studies of RGO also showed blue light emission [16] and infrared absorption [17,18] determined by the size, shape and edge configuration sp 2 graphitic domain. All these studies clearly suggest that RGO should behave as a two dimensional array of graphene quantum dots (GQD), which should be verified from low temperature electron transport measurements.…”

Efros-Shklovskii variable-range hopping in reduced graphene oxide sheets of varying carbonsp2fraction

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] In particular, solution processed route for producing reduced graphene oxide (RGO) sheets, which has a wide range of oxygen functionalities such as hydroxyl and epoxy groups, received great attention due to its (i) high throughput manufacturing, (ii) tunable electrical and optical properties via controlling the ratio of sp 2 C-C and sp 3 hybridized carbon (i.e., oxygen functional groups) and (iii) ability to anchor different types of nanoparticles and organic molecules, which pave the way for potential applications in flexible electronics, photovoltaics, supercapacitors and battery. 1,2,15,[18][19][20][21][22][23][24][25][26][27][28] Functionalization of graphene creates disorders and the low temperature electronic transport properties of these structures are akin to that of disordered semiconductors where electron localization and hopping conduction play a significant role. However, a clear understanding of the electronic transport properties of the RGO sheets is lacking as different study reports different conduction mechanisms such as Mott variable range hopping (VRH) and Efros-Shklovskii (ES-) VRH.…”

Graphene oxide/carbon nanoparticle thin film based IR detector: Surface properties and device characterization

“…In first 5 secs the current increased 2 times which is twice as much higher as compared to the performance obtained from only reduced graphene oxide detector as reported before. 56,57 In 10 seconds the current increases 12 times of the first count and increases linearly for the first 60 seconds. After that, the current increases gradually for another 10 minutes.…”

“…After that, the current increases gradually for another 10 minutes. The rise of current due to body irradiation with time fits with the equation of exponential growth I(t) = I 0 + C(1 -exp(-t/τ C ) +D(1 -exp(-t/τ D )); where t is the time when hand was taken to proximity of the film, τ is the time constant, I 0 is the current before irradiation by the body (dark current), 56,57 C, D are scaling constants. The 'τ' is defined as the amount of time required for holes inflowing the electrode.…”

“…In the present study recombination/generation of electron-hole pairs when exposed to human body radiation is the plausible phenomena to detect radiation emitted by the body. 56,57 Figures (1,2,3) were produced using the program WSxM.…”