Improved liquid phase exfoliation technique for the fabrication of MoS(2)/graphene heterostructure-based photodetector.

2D nanosheets produced using liquid phase exfoliation method offers scalable and cost effective routes to optoelectronics devices. But this technique sometimes yields high defect, low stability, and compromised electronic properties. In this work, we employed an innovative approach that improved the existing liquid phase exfoliation method for fabricating MoS2/graphene heterostructure-based photodetector with enhanced optoelectronic properties. This technique involves hydrothermally treating MoS2 before dispersing it in a carefully chosen and environmentally friendly IPA/water solvent for ultrasonication exfoliation through an optomechanical approach. Thereafter, heterostructure nanosheets of MoS2 and graphene were formed through sequential deposition technique for the fabrication of vertical heterojunctions. Furthermore, we achieved a vertically stacked MoS2/graphene photodetector and a bare MoS2 photodetector. The MoS2/graphene hybrid nanosheets were characterized using spectroscopic and microscopic techniques. The results obtained show the size of the nanosheets is between 350 and 500 nm on average, and their thickness is less than or equal to 5 nm, and high crystallinity in the 2H semiconducting phase. The photocurrent, photoresponsivity, external quantum efficiency (EQE), and specific detectivity of MoS2/graphene heterostructure at 4 V bias voltage and 650 nm illumination wavelength were 3.55 μA, 39.44 mA/W, 7.54 %, and 2.02 × 1010 Jones, respectively, and that of MoS2 photodetector are 0.55 μA, 6.11 mA/W, 1.16 %, and 3.4 × 109 Jones. The results presented indicate that the photoresponse performances of the as-prepared MoS2/graphene were greatly improved (about 7-fold) compared to the photoresponse of the sole MoS2. Again, the MoS2/graphene heterostructure fabricated in this work show better optoelectronic characteristics as compared to the similar heterostructure prepared using the conventional solution processed method. The results provide a modest, inexpensive, and efficient method to fabricate heterojunctions with improved optoelectronic performance.

Akeredolu BJ ，Ahemen I ，Amah AN ，Onojah AD ，Shakya J ，Gayathri HN ，Ghosh A ... -  《Heliyon》

Solution-processed MoS(2) quantum dot/GaAs vertical heterostructure based self-powered photodetectors with superior detectivity.

Sarkar SS ，Mukherjee S ，Khatri RK ，Ray SK ... -  《-》

Photophysical Dynamics in Semiconducting Graphene Quantum Dots Integrated with 2D MoS(2) for Optical Enhancement in the Near UV.

Min M ，Sakri S ，Saenz GA ，Kaul AB ... -  《-》

Photoresponse-Bias Modulation of a High-Performance MoS(2) Photodetector with a Unique Vertically Stacked 2H-MoS(2)/1T@2H-MoS(2) Structure.

Wang W ，Zeng X ，Warner JH ，Guo Z ，Hu Y ，Zeng Y ，Lu J ，Jin W ，Wang S ，Lu J ，Zeng Y ，Xiao Y ... -  《-》

High Detectivity and Transparent Few-Layer MoS(2) /Glassy-Graphene Heterostructure Photodetectors.

Layered van der Waals heterostructures have attracted considerable attention recently, due to their unique properties both inherited from individual two-dimensional (2D) components and imparted from their interactions. Here, a novel few-layer MoS2 /glassy-graphene heterostructure, synthesized by a layer-by-layer transfer technique, and its application as transparent photodetectors are reported for the first time. Instead of a traditional Schottky junction, coherent ohmic contact is formed at the interface between the MoS2 and the glassy-graphene nanosheets. The device exhibits pronounced wavelength selectivity as illuminated by monochromatic lights. A responsivity of 12.3 mA W-1 and detectivity of 1.8 × 1010 Jones are obtained from the photodetector under 532 nm light illumination. Density functional theory calculations reveal the impact of specific carbon atomic arrangement in the glassy-graphene on the electronic band structure. It is demonstrated that the band alignment of the layered heterostructures can be manipulated by lattice engineering of 2D nanosheets to enhance optoelectronic performance.

Xu H ，Han X ，Dai X ，Liu W ，Wu J ，Zhu J ，Kim D ，Zou G ，Sablon KA ，Sergeev A ，Guo Z ，Liu H ... -  《-》