Photoelectrical response of hybrid graphene-PbS quantum dot devices

Abstract

Hybrid graphene-PbS quantum dot devices are fabricated on an n-type silicon substrate capped with a thin SiO2 layer and are characterized by photoelectrical measurements. It is shown that the resistance of the graphene channel in the devices exhibits detectable changes when a laser beam is switched on and off on the quantum dots. The model that explains the observed photoresponse phenomenon is illustrated. We also show that the photoresponse signal, i.e., the photoinduced change in the resistance of the graphene channel can be tuned in both magnitude and sign with a voltage applied to the back gate of the devices and is related to the derivative of the transfer characteristics of the graphene channel. Our work shows that the simple hybrid graphene-PbS quantum dot devices can be employed for photodetection applications.

High-response hybrid quantum dots- 2D conductor phototransistors: recent progress and perspectives

“…Let us note that the analogous shifts of the gate voltage due to QD deposition doping and light-induced doping of graphene were observed in Refs. [61] and [62]. The main conclusion of the model [7] is that because the light-induced process is realized due to the electric field created by QD deposition, the light-induced charge transfer (Dirac voltage) is opposite to the charge transfer related to QD deposition on graphene.…”

“…Devices having a graphene channel and PbS QDs were also investigated in Refs. [10,[61][62][63]. In other works, the graphene channel was combined with ZnO QDs [28,64] and recently with PbSe QDs [25,65].…”

“…In particular, ligands of the amine group are relatively long, and even in the QD nanomaterial [23], (B) [10], and (C) [62]; (D) integrating diode-transistor detector based on graphene with PbS QDs [68].…”

Electron–Hole Symmetry Breaking in Charge Transport in Nitrogen-Doped Graphene

“…[6][7][8][9][10] A particular case is when approaching the Dirac point at which, because of the vanishing density of states, the transport properties of graphene are expected to be highly sensitive to 3 scattering from charged impurities. [6][7][8][9][10] Previous studies of charge carrier scattering in graphene are mainly achieved with the scattering centers introduced by physical methods, such as ion irradiation, 7, 8 adsorption of adlayers, 9 low temperature deposition 10 and spin coating [11][12][13] of nanoparticles, and atomic hydrogen adsorption. 14 These methods could inevitably induce randomness and disorder in graphene and thereby largely degrade its transport properties.…”

Material and Device Architecture Engineering Toward High Performance Two-Dimensional (2D) Photodetectors

“…However, the gapless nature of intrinsic graphene and the limited light absorption in each atomic layer prevent efficient photocarrier separation in graphene photodetectors. To overcome this shortcoming, the integration of graphene with other materials appears to be a promising approach [70,71], such as quantum dots/graphene [72,73], MoS 2 /graphene [12], WSe 2 /graphene [71] and Bi 2 Te 3 /graphene [74] heterojunctions. One easy and functional approach for fabrication of these heterojunctions is by reattaching the different films onto each other [12].…”