Photoconduction Properties in Tungsten Disulfide Nanostructures.

We reported the photoconduction properties of tungsten disulfide (WS) nanoflakes obtained by the mechanical exfoliation method. The photocurrent measurements were carried out using a 532 nm laser source with different illumination powers. The results reveal a linear dependence of photocurrent on the excitation power, and the photoresponsivity shows an independent behavior at higher light intensities (400-4000 Wm).

Photoconductivities in MoS2 Nanoflake Photoconductors.

Photoconductivities in molybdenum disulfide (MoS2) layered nanostructures with two-hexagonal crystalline structure prepared by mechanical exfoliation were investigated. The photoconductor-type MoS2 nanoflakes exhibit remarkable photoresponse under the above bandgap excitation wavelength of 532 nm at different optical intensity. The photocurrent responsivity and photoconductive gain of nanoflakes can reach, respectively, 30 AW(-1) and 103 at the intensity of 50 Wm(-2), which are several orders of magnitude higher than those of their bulk counterparts.

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures.

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor performance, which suggest a new direction for the development of next-generation ultrathin and flexible photonic and electronic devices. Enhanced luminescence quantum efficiency has been widely observed in these atomically thin 2D crystals. However, dimension effects beyond quantum confinement thicknesses or even at the micrometer scale are not expected and have rarely been observed.

Thickness-dependent electrical conductivities and ohmic contacts in transition metal dichalcogenides multilayers.

We report on the observation of the substantial thickness (t)-dependent electrical conductivity (σ) at a wide thickness range for an MoSe₂ layer semiconductor. The conductivity increases for more than two orders of magnitude from 4.6 to 1500 Ω(-1) cm(-1) with a decrease in thickness from 2700 to 6 nm.