Photon-generated carrier transfer process from graphene to quantum dots : optical evidences and ultrafast photonics applications
Abstract
Graphene/III–V semiconductor van der Waals (vdW) heterostructures offer potential access to physics, functionalities, and superior performance of optoelectronic devices. Nevertheless, the lack of a bandgap in graphene severely restricts the controllability of carrier properties and therefore impedes its applications. Here, we demonstrate the engineering of graphene bandgap in the graphene/GaAs heterostructure via C and Ga exchange induced by the method of femtosecond laser irradiation (FLI). The coupling of the bandgap-opened graphene with GaAs significantly enhances both the harvest of photons and the transfer of photon-generated carriers across the interface of vdW heterostructures. Thus, as a demonstration example, it allows us to develop a saturable absorber combining a delicately engineered graphene/GaAs vdW heterostructure with InAs quantum dots capped with short-period superlattices. This device exhibits significantly improved nonlinear characteristics including <1/3 saturation intensity and modulation depth 20 times greater than previously reported semiconductor saturable absorber mirrors. This work not only opens the route for the future development of even higher performance mode-locked lasers, but the significantly enhanced nonlinear characteristics due to doping-induced bandgap opening of graphene by FLI in the vdW heterostructures will also inspire wide applications in photonic and optoelectronic devices.
Citation
Wang , X , Li , X H , Jiang , C , Brown , C T A , Ning , J Q , Zhang , K , Yu , Q , Ge , X T , Wang , Q J & Zhang , Z Y 2020 , ' Photon-generated carrier transfer process from graphene to quantum dots : optical evidences and ultrafast photonics applications ' , npj 2D Materials and Applications , vol. 4 , 27 . https://doi.org/10.1038/s41699-020-00160-6
Publication
npj 2D Materials and Applications
Status
Peer reviewed
ISSN
2397-7132Type
Journal article
Description
The authors acknowledge Natural Science Foundation of China (Grant Nos. 61875222, 61875223, 61605106, 11874390).Collections
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.