Atomic‐Scale Characterization of Negative Differential Resistance in Ferroelectric Bi₂WO₆

Abstract

Negative differential resistance (NDR), a quantum nonlinear electron transport process, has long attracted research interest owing to its intriguing underlying physics and promising applications in high-speed electronics. Here, the authors report the NDR behavior in (001)-oriented ferroelectric Bi 2 WO 6 using scanning tunneling microscopy (STM). The current-voltage characteristics of the diode configuration consisting of an STM tip over the [BiO] + -[WO 4 ] 2− -[BiO] + terrace exhibit NDR features. Scanning tunneling spectroscopy combined with density functional theory calculations indicates that the observed NDR results from robust resonant tunneling through confined energy levels within the 2D [WO 4 ] 2− layer. The atomically resolved NDR found in such a transition metal oxide offers a unique band structure for novel ferroelectric-based devices.

Atomic‐Scale Visualization of Multiferroicity in Monolayer NiI2

“…The negative conductance occurring at high bias can be associated with the resonant tunneling through confined energy levels within the 2D layer. [ 46 ] Figure 2c,d shows small‐area STM images at 0.3 V (within the NiI 2 bandgap) and at 0.9 V (within the NiI 2 conduction band). A systematic analysis with scans at different energies can be found in the Supporting Information.…”

Photoinduced Negative Differential Resistivity and Gunn Oscillations in SrTiO3

“…[ 15 ] This type of NDR is usually produced in classical bulk semiconductors by a transferred‐electron effect or in special quantum tunnel devices such as Esaki or resonant tunneling diodes. [ 16,17 ] In the present case the device is pure bulk, thus the type is the voltage controlled NDR generated by a transferred‐electron effect. The mechanism behind, called Ridley–Watkins mechanism, [ 18 ] is characterized by transfer of free electrons from the high mobility energy valley of the energy band structure to a low‐mobility, higher energy satellite valley.…”

“…This is most probably generated by an intervalley transfer of photo‐induced electrons similar to Ridley and Walking mechanism. [ 17 ] As in the case of classical semiconductors, soon the system enters the NDR regime the photocurrent becomes instable generating Gunn‐like oscillations. The oscillation frequencies are rather low due to existence of at least one active impurity level within the band gap which limits the velocity of the Gunn domains.…”

Design of an interface heating device based on polydivinylbenzene/SiO2/Bi2WO6and its visible light response performance for water purification

“…38–43 Bi 2 WO 6 has stable physicochemical properties, which have been applied in fields such as CO 2 reduction, 44 water oxidation, 45 the electrocatalytic production of NH 3 , 46 multiferroicity at room temperature, 47 pollutant photodegradation 48,49 and negative differential resistance. 50 Powder Bi 2 WO 6 needs to be dispersed in a solution during the dye degradation process, which brings inconvenience to reuse. In order to form a bulk photocatalyst, Chu et al 51 adopted PTFE as the binder, and the immobilized Bi 2 WO 6 /BiOI/g-C 3 N 4 had a stable mechanical strength as well as a degradation capacity.…”