Study for the electrical and optical properties of the specimens with graphene quantum dots prepared by different number of wet transfer

Abstract

In the present study graphene quantum dots (GQDs) are grown on the copper foil substrate by the chemical vapor deposition (CVD) synthesis 1~3 wet transfer numbers are then used in the preparations of the GQDs/glass substrates in order to improve the density and uniformity of GQDs via the stacking of multiple layers The CH4 input time flow rate and the number of wet transfer are determined in sequence to obtain the optimum conditions in electrical (resistivity) and optical (transmittance) properties All particles irrespective of the number of wet transfer are identified to be the graphene(110) The multilayered graphene is characteristically close to the graphite-like material The G-band peak intensity in Raman analyses is varied proportional to the density of GQDs The hopping and edge defects are identified to be existing in GQDs and the D-band related to the edge defect is lowered by increasing the number of wet transfer Increasing the wet transfer number can lead to the rise of the mean diameter of GQDs and the amount of oxygen vacancies thus resulting in the increase of carrier concentration and the drop of carrier mobility The resistivity varying with the number of wet transfer is inversely proportional to the density of GQDs Bandgap energy is slightly lowered by increasing the number of wet transfer A bandgap reduction can bring in the lowering of photoluminescence peak intensities of green and red The mean transmittance of specimen is slightly lowered by increasing the number of wet transfer The specimen with 2 wet transfers has the lowest resistivity and the second highest transmittance of these specimens GQDs can bring in a significant reduction of resistivity compared to the same substrate but without GQD

Date of Award	2019
Original language	English
Supervisor	Jen-Fin Lin (Supervisor)