  Interface of transition metal dichalcogenide (TMDC) and high-k dielectric
transition metal oxides (TMO) had triggerred umpteen discourses due to the
indubitable impact of TMO in reducing the contact resistances and restraining
the Fermi-level pinning for the metal-TMDC contacts. In the present work, we
focus on the unresolved tumults of large-area TMDC/TMO interfaces, grown by
adopting different techniques. Here, on a pulsed laser deposited (PLD) MoS2
thin film, a layer of TiO2 is grown by using both atomic layer deposition (ALD)
and PLD. These two different techniques emanate TiO2 layers with different
crystalline properties, thicknesses and interfacial morphologies, subsequently
influencing the electronic and optical properties of the interfaces. In
addition, they manifest a boost in the extent of p-type doping with increasing
thickness of TiO2, as emerged after analyzing the core-level shifts of the
X-ray photoelectron spectra (XPS). Density functional analysis of the
MoS2/Anatase-TiO2 interfaces, for pristine and in presence of a wide range of
interfacial defects, could explain the interdependence of doping and the
terminating atomic-surface of TiO2 on MoS2. The optical properties of the
interface, encompassing the photoluminescence, transient absorption and z-scan
two-photon absorption indicate the presence of defect-induced localized mid-gap
levels in MoS2/TiO2 (PLD), resulting quenched exciton signals. On the contrary,
the relatively defect-free interface in MoS2/TiO2 (ALD) demonstrates a clear
presence of both A and B excitons of MoS2. From the investigation of optical
properties, we indicate that MoS2/TiO2 (PLD) interface may act as a promising
saturable absorber. Moreover, MoS2/TiO2 (PLD) interface had resulted a better
photo-transport. A potential application of MoS2/TiO2 (PLD) is demonstrated by
the fabrication of a p-type photo-transistor with the ionic-gel top gate.
