Optically Controllable 2D Material/Complex Oxide Heterointerface

Abstract

Heterostructures play a vital role in functional devices on the basis of the individual constituents. Non‐conventional heterostructures formed by stacking 2D materials onto structurally distinct materials are of great interest in achieving novel phenomena that are both scientifically and technologically relevant. Here, a heterostructure based on a 2D (molybdenum ditelluride) MoTe 2 and an amorphous strontium titanium oxide (a‐STO) thin film is reported. The heterostructure functions as a high‐performance photodetector, which exhibits anomalous negative photoresponse in the pristine device due to the scattering effect from the light‐induced O δ‐ ions. The photoresponsivity and the specific detectivity are found to be >10 4 AW ‐1 and >10 13 Jones, respectively, which are significantly higher than those in standard MoTe 2 devices. Moreover, through tuning the light programming time, the photodetection behavior of the MoTe 2 /a‐STO heterostructure experiences a dynamic evolution from negative to positive. This is due to the optically controllable modulation of the interfacial states, which is further confirmed by the X‐ray photoelectron spectroscopy and photoluminescence measurements. It is envisioned that the 2D material/a‐STO heterostructure could be a potential platform for exploring new functional devices.

A Wavelength‐Tunable Multi‐Functional Transistor with Visible‐Light Detection and Inverse Photomemory for Logic Gate and Retina Emulation

“…[ 10,11 ] Because of the π‐π conjugated structures and the band gaps in OSC molecules, light with a specific wavelength can be adsorbed and induce photoelectric effects in OFETs. [ 12,13 ] Based on the initial optoelectronic properties of OSCs and the trapping effect of the OSC/dielectric interface, [ 14–16 ] organic phototransistors have been widely investigated as essential units in the applications of photodetectors, [ 17–21 ] photomemory device, [ 22,23 ] solar cell, [ 24,25 ] and photosynaptic transistors. [ 26–28 ] Wakayama group gave an essential summary of phototransistors.…”

An ultrasensitive molybdenum-based double-heterojunction phototransistor

“…Photodetectors based on two-dimensional (2D) materials usually have a low responsivity and detectivity 1 – 3 because atomically-thin 2D layered materials have weak light absorption. The photogating mechanism has been widely used to provide a photo gain to improve device performance 4 – 6 , which is basically achieved either by a trap-assisted photoconductive effect 7 – 27 or by a photovoltaic effect 28 . For example, charges were transferred from the channel to the bound water molecules on the SiO 2 surface in pristine MoS 2 phototransistors 7 , and the poor charge separation ability of water molecules leads to a relatively low detectivity.…”

Research progress on two-dimensional indium selenide crystals and optoelectronic devices

“…PLD is a typical bottom-up physical method widely used for the deposition of 2D layered materials and complex compound thin lms. [82][83][84] As shown in Fig. 6(c), layered InSe lms were deposited on SiO 2 (300 nm)/Si substrates in a high vacuum chamber with a pressure of 1.5 × 10 −7 Torr.…”