Molybdenum disulfide (MoS) film fabricated by a liquid exfoliation method has significant potential for various applications, because of its advantages of mass production and low-temperature processes. In this study, residue-free MoS thin films were formed during the liquid exfoliation process and their electrical properties were characterized with an interdigitated electrode. Then, the MoS film thickness could be controlled by centrifuge condition in the range of 20 ∼ 40 nm, and its carrier concentration and mobility were measured at about 7.36 × 10 cm and 4.67 cm V s, respectively. Detailed analysis on the films was done by atomic force microscopy, Raman spectroscopy, and high-resolution transmission electron microscopy measurements for verifying the film quality. For application of the photovoltaic device, a Au/MoS/silicon/In junction structure was fabricated, which then showed power conversion efficiency of 1.01% under illumination of 100 mW cm.

We report an enhancement of near-infrared (NIR) detectability from amorphous InGaZnO (α-IGZO) thin film transistor in conjunction with randomly distributed molybdenum disulfide (MoS) flakes. The electrical characteristics of the α-IGZO grown by radio-frequency magnetron sputtering exhibit high effective mobility exceeding 15 cm V s and current on/off ratio up to 10. By taking advantages of the high quality α-IGZO and MoS light absorbing layer, photodetection spectra are able to extend from ultra-violet to NIR range. The α-IGZO channel detector capped by MoS show a photo-responsivity of approximately 14.9 mA W at 1100 nm wavelength, which is five times higher than of the α-IGZO device without MoS layer.

We investigated a vertically stacked p+-n heterojunction diode consisting of a two-dimensional (2D) molybdenum disulfide (MoS2) crystal and a heavily doped p+-type Si substrate. The MoS2 flakes are transferred onto p+-Si substrates by using a scotch tape-based exfoliation method. The performances of n-MoS2/p+-Si diodes are investigated by I-V measurement under light illumination using light emitting diodes with various wavelengths. It appears that multilayer MoS2 has sufficient thickness to absorb incident light from the visible to near-infrared range with a high sensitivity. With the advantages of a simple device structure as well as improved contact quality between the MoS2 and silicon interface, an ideality factor of 1.09 can be achieved. The diodes reveal an ultra-high photoresponsivity of about 980 A/W at a wavelength of 525 nm with a strong dependence on the light wavelength and intensity, while they show a high specific detectivity on the order of 109 cm·Hz1/2/W from the visible to near infrared spectral ranges.

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