Fig. 1: Materials and devices for transient spectroscopic study of defects.
From: Chemical trends of deep levels in van der Waals semiconductors
a Schematic and optical image (scale bar: 20 μm) of an asymmetric MoS2 device for DLTS, with Schottky contact (MoS2/Pt/Ti) on the bottom and Ohmic contact (Au/Ti/MoS2) on the top. b Aberration-corrected STEM image of a monolayer MoS2 exfoliated from the materials used for devices. Red arrows highlight S vacancies (VS). Scale bar, 1 nm. c Capacitance transient (bottom) in response to a pulsed change in bias voltage (top). d Band bending of the Schottky junction (MoS2/Pt), illustrating the electron trapping (②) and emission process (③) of deep traps in the depletion region (shaded). VR tunes the Fermi level of the n-type MoS2 (EFn) with respect to that of the metal contact (EFm). e & f, Temperature-dependent I–V and C–V curves confirming the Schottky-Ohmic contacts.
