Camphor-Based CVD Bilayer Graphene/Si Heterostructures for Self-Powered and Broadband Photodetection

Abstract

This work demonstrates a self-powered and broadband photodetector using a heterojunction formed by camphor-based chemical vaper deposition (CVD) bilayer graphene on p-Si substrates. Here, graphene/p-Si heterostructures and graphene layers serve as ultra-shallow junctions for UV absorption and zero bandgap junction materials (<Si bandgap (1.1 eV)) for long-wave near-infrared (LWNIR) absorption, respectively. According to the Raman spectra and large-area (16 × 16 μm2) Raman mapping, a low-defect, >95% coverage bilayer and high-uniformity graphene were successfully obtained by camphor-based CVD processes. Furthermore, the carrier mobility of the camphor-based CVD bilayer graphene at room temperature is 1.8 × 103 cm2/V·s. Due to the incorporation of camphor-based CVD graphene, the graphene/p-Si Schottky junctions show a good rectification property (rectification ratio of ~110 at ± 2 V) and good performance as a self-powered (under zero bias) photodetector from UV to LWNIR. The photocurrent to dark current ratio (PDCR) value is up to 230 at 0 V under white light illumination, and the detectivity (D*) is 8 × 1012 cmHz1/2/W at 560 nm. Furthermore, the photodetector (PD) response/decay time (i.e., rise/fall time) is ~118/120 μs. These results support the camphor-based CVD bilayer graphene/Si Schottky PDs for use in self-powered and ultra-broadband light detection in the future.

Bifunctional enhancement of photodetection and photovoltaic parameters in graphene/porous-Si heterostructures by employing interfacial hexagonal boron nitride and bathocuproine back-surface passivation layers

“…It should be noted that the highest D * is almost 100 times enhanced by the inclusion of the h-BN and BCP, and is comparable to or larger than those ever achieved in self-powered GR/Si-heterojunction PDs (Table S1, ESI†). 17,38–42…”

Ultrafast and Reversible Superwettability Switching of 3D Graphene Foams via Solvent-Exclusive Plasma Treatments

“…To meet the need for reversible wettability transition, − chemisorption and desorption of wettability-related groups are of interest. For the chemisorption of oxygen radicals or hydroxyl groups, ultraviolet irradiation has been frequently applied in water vapor or O 3 gas; the shallow penetration depth, however, makes this process time-consuming (≥1 h) even for 2D graphene . Although the use of air or O 2 plasmas reduces the reaction time, ,, the shallow penetration depth still renders the methodology applicable for ultrathin films only. , Furthermore, the desorption of hydrophilic groups is even more time-consuming as an extreme endothermic process, and a four-day vacuum treatment is necessary for fully desorbing hydroxyl groups from the graphene surface .…”

Multifunctional and High‐Performance FAPBI3 Quantum Dots/Graphene UV Photodetectors by the Modulation of Photoconductivity

“…[41][42][43][44] In the atmospheric environment, the graphene synthesized by chemical vapor deposition (CVD) contains many oxygen-containing functional groups, such as -OH and -COOH. [45][46][47][48] These functional groups combine with electrons in the valence band of graphene to form stable chemical bonds, and graphene also has a vital water absorption characteristic. [49][50][51] Water exists in the form of H 3 O + on the graphene surface and absorbs electrons to maintain electrical neutrality.…”