Bilayer graphene based surface passivation enhanced nano structured self-powered near-infrared photodetector

Abstract

A simple methyl-terminated (-CH(3)) surface passivation approach has been employed to enhance the performance of the bilayer graphene/Si nanohole array (BLG/SiNH array) Schottky junction based self-powered near infrared photodetector (SPNIRPD). The as-fabricated SPNIRPD exhibits high sensitivity to light at near infrared region at zero bias voltage. The I(light)/I(dark) ratio measured is 1.43 × 10(7), which is more than an order of magnitude improvement compared with the sample without passivation (~6.4 × 10(5)). Its corresponding responsivity and detectivity are 0.328 AW(-1) and 6.03 × 10(13) cmHz(1/2)W(-1), respectively. The demonstrated results have confirmed the high-performance SPNIRPD compared with the photo-detectors of similar type and its great potential application in future optoelectronic devices.

High-responsivity UV-Vis Photodetector Based on Transferable WS2 Film Deposited by Magnetron Sputtering

“…Moreover, to determine the sensibility of detecting a weak optical signal, the specific detectivity ( D* ) is measured and calculated. By assuming that shot noise from dark current constitutes a major contribution to the total noise, D * can be expressed in the form of D * = A 1/2 R /(2 qI dark ) 1 / 2 , where R is the responsivity, A is the effective area of the detector, q is the absolute value of electron charge, and I dark is the dark current 33 . The D* is calculated to be 1.22 × 10 11 Jones at a luminescent light intensity of 12.1 μW/cm 2 at 365 nm and a bias voltage of 5 V. These results are superior or comparable to the previously reported photodetectors that are fabricated on the basis of 2D TMDs, as listed in Table 1 .…”

Technique and model for modifying the saturable absorption (SA) properties of 2D nanofilms by considering interband exciton recombination

“…F 0 is the laser fluence at z = 0, and F on 0 and DT 0 are the values of F on and DT for the pulse width t = 100 fs. The analytical expressions (4) and (5) show the regular variation of the SA parameters F on and DT with the excitation pulse width t. For the 5 min WS 2 film, T L = 60.97%, a = 0.3903, F on 0 = 2.73 mJ cm À2 , F 0 = 73.9 mJ cm À2 , T 0 0 = 80.54%, A 1 = 67.5%, t 1 = 512 ps, A 2 = 26.2%, t 2 = 1311 ps, A 3 = 6.3%, and t 3 = 2883 ps. Substituting these parameters into eqn (4) and (5) produces the two solid curves shown in Fig.…”

“…2D materials exhibit exceptional electrical and optical properties compared to their bulk forms due to the quantum confinement perpendicular to the 2D plane. 1 Soon after the discovery of graphene in 2004, 2,3 scientists demonstrated advanced electric and photonic applications such as photodetectors, [4][5][6][7][8] lightemitting diodes, 9 phototransistors, 10,11 solar cells, 12 optical waveguides, 13 and ultrafast lasers 14 by using graphene. However, the zero-bandgap nature and low layer optical absorption of graphene limits its application in the field of photonics and nonlinear optics.…”

Applications of Graphene in Self-Powered Sensing Systems

“…Type of sensors Graphene materials The roles of graphene Electrochemical Strain sensor [21][22][23] Graphene foam, graphenepolymer composite film Flexible piezoresistive electrode with high conductivity and strain sensitivity Humidity sensor 24 Graphene oxide film High specific surface area, surface functional groups that can rapidly capture and transfer water molecules Photovoltaic Photodetector [25][26][27][28][29][30][31][32][33][34] Monolayer / few-layer graphene Coupling with other semiconductor surfaces to form various Schottky junctions Monolayer / few-layer graphene Transparent conductive electrode with excellent light transmission, conductivity and flexibility Gas sensor 35 Graphene film Doping effect on the adsorption of gas molecules Position sensor 36 Reduced graphene oxide film Lateral photovoltaic effect Triboelectric Deformation sensor [37][38][39] Graphene quantum dot, film Flexible conductive electrodes Pressure sensor 40 Graphene foam Highly sensitive piezoresistive performance Touch sensor 20,41 Monolayer graphene, interlocked percolative graphene Building capacitive sensing arrays or piezoresistive sensing arrays Humidity sensor 42 Graphene-SnS2 composite Moisture-sensitive conductive network Gas sensor 43 Graphene-metal oxide composite Gas-sensitive conductive network Hydrovoltaic Fluid sensor 9,44 Monolayer graphene Liquid flow-induced electricity (drawing potential) Concentration sensor 9,18 Monolayer graphene Ion adsorption on liquid-graphene interface Humidity sensor [45][46][47] Graphene oxide film or framework Surface functional groups interact with ambient moisture to generate electric signal Thermoelectric Strain sensor 48 Graphene-polymer composite film Thermoelectricity and excellent electromechanical coupling performance Tempera...…”

“…Adapted with permission from Ref. 24 28 . (e) A graphene/GaAs nanowires array Schottky junction photodetector, (f) the band alignment of (e) 29 .…”