Spatially Bandgap-Graded MoS2(1−x)Se2x Homojunctions for Self-Powered Visible–Near-Infrared Phototransistors

Abstract

HIGHLIGHTS • Due to the Se composition and thickness gradient within single MoS 2(1−x) Se 2x domains, the bandgap of MoS 2(1−x) Se 2x is gradually tuned from 1.83 to 1.73 eV. • The homojunction phototransistors at zero bias deliver a photoresponsivity of 311 mA W −1 , a specific detectivity up to ~ 10 11 Jones, and an on/off ratio up to ~ 10 4. • The biased devices yield a champion photoresponsivity of 191.5 A W −1 , a specific detectivity up to ~ 10 12 Jones, and a photoconductive gain of 10 6-10 7 .

A review of molybdenum disulfide (MoS2) based photodetectors: from ultra-broadband, self-powered to flexible devices

“…The photocurrents of MoSSe alloy based photodetectors were considerably increased compared with pure MoS 2 and MoSe 2 based photodetectors. The photoresponsivity of CVD-grown Au/MoS 1.15 Se 0.85 /Au based photodetectors was found to be much higher, 2.06 Â 10 3 mA W À1 at 532 nm with rise/fall times of 18 s/35 s. 386 In another study by Xu et al, 435 the bandgap of MoS 2(1Àx) Se 2x was tailored between 1.83 eV to 1.73 eV by adjusting the Se composition and thickness within a single domain. The spatially bandgap-graded MoS 2(1Àx) Se 2x based phototransistors showed photoresponsivity of 191.5 A W À1 , detectivity of 10 12 Jones, photoconductive gain of 10 6 to 10 7 and response speed of 51 ms under À0.5 V bias voltage.…”

“…221,258,272 MoS 2 based self-powered broadband photodetectors have been reported for n-MoS 2 /n-GaAs, 438 MoS 2 /b-Ga 2 O 3 , 439 Pd-MoS 2 /Si, 440 Pd/Al 2 O 3 /MoS 2 , 441 Pd/HfO 2 /MoS 2 , 441 graphene/InSe/MoS 2 , 442 p-Cu 9 S 5 /n-MoS 2 , 443 and MoS 2(1Àx) -Se 2x . 385,386,435 MoS 2 based self-powered photodetectors exhibit photoresponsivity from mA W À1 to A W À1 , detectivity from 10 9 to 10 15 Jones and response time from microseconds (ms) to seconds (s), depending on the measurement wavelengths and incident power densities which could be used for healthcare applications.…”

Recent Advances in 2D MXenes for Photodetection

“…[ 5–7 ] Since the first exfoliation of graphene, not only novel materials, including black phosphorene, silicene, stanene, and h‐BN, has emerged, but also the strong interests in transition metal dichalcogenides (TMDs) have resurged. [ 8–11 ] As a relatively new branch of 2D materials, transition metal carbides, carbonitrides, and nitrides were first discovered and termed MXenes by Barsoum et al in 2011. [ 12 ]…”

Performance Improvements of Cobalt Oxide Cathodes for Rechargeable Lithium Batteries

“…LiCoO 2 coated with 2.0 wt % yttria-stabilized zirconia also delivered a stable capacity of 160 mAh g -1 between 2.75 V and 4.4 V and a good cycle stability for 142 cycles [106]. Nevertheless, metal oxide coatings, although suppressing the interfacial side reactions, tend to be discontinuously deposited on the surface of the cathode material [107][108][109]. Thick and continuous coating can reduce the exothermic reaction between the cathode and the electrolyte, but the electronic resistance is increased due to the poor electronic conductivity of metal oxide coatings [110,111].…”