Controlled Polarizability of One‐Nanometer‐Thick Oxide Nanosheets for Tailored, High‐κ Nanodielectrics

Abstract

An important challenge in current microelectronics research is the development of techniques for making smaller, higher-performance electronic components. In this context, the fabrication and integration of ultrathin high-κ dielectrics with good insulating properties is an important issue. Here, we report on a rational approach to produce high-performance nanodielectrics using one-nanometer-thick oxide nanosheets as a building block. In titano niobate nanosheets (TiNbO 5 , Ti 2 NbO 7 , Ti 5 NbO 14 ), the octahedral distortion inherent to site-engineering by Nb incorporation results in a giant molecular polarizability, and their multilayer nanofi lms exhibit a high dielectric constant (160-320), the largest value seen so far in high-κ nanofi lms with thickness down to 10 nm. Furthermore, these superior high-κ properties are fairly temperature-independent with low leakage-current density ( < 10 − 7 A cm − 2 ). This work may provide a new recipe for designing nanodielectrics desirable for practical high-κ devices.

Recent development in 2D materials beyond graphene

“…AFM is an influential technique to identify layer thickness ( Figure. 13b, c) with 5% preciseness [214][215][216][217]. However, inconsistencies originate from dissimilarities in the tip interactions with substrate and the layered materials [218].…”

“…This is used to detect below surface defects, regions of suspension and measure mechanical coupling of 2D materials with the substrate [219,[222][223][224]. Others, used this technique to the show weak mechanical bonding between the substrate and the layers for free standing sheets and strong mechanical bonding when a dielectric capping layer is added [214,215,225].…”

“…Unlike SEM, where secondary electrons are emitted from the sample surface, electrons in TEM are transmitted through the entire sample; usually after the sample has been thinned to nm thickness. The electrons interact with the atoms during transmission and deflection can be used to produce an image [215]. TEM has a higher resolution compared to SEM as high voltage (200-300kV) is used to generate electrons in TEM which has a shorter wavelength and thus enhance the resolution , but requires samples to be extremely thin (<200 nm) which is a disadvantage for many systems [225].…”

Controlled Exfoliation of Layered Silicate Heterostructures into Bilayers and Their Conversion into Giant Janus Platelets

“…[40][41][42][43][44] By cleaving bilayers with appropriate reagents, in this case bases,the symmetry is broken in the simplest way, giving access to ag eneral method for the synthesis of asymmetrically modified Janus nanoplatelets with tuneable functionalities. Thesynthesis route for bilayers will be generally applicable to other layered compounds capable of osmotic swelling,s uch as layered titanates,n iobates,o rp erovskites.…”

“…Thesynthesis route for bilayers will be generally applicable to other layered compounds capable of osmotic swelling,s uch as layered titanates,n iobates,o rp erovskites. [40][41][42][43][44] By cleaving bilayers with appropriate reagents, in this case bases,the symmetry is broken in the simplest way, giving access to ag eneral method for the synthesis of asymmetrically modified Janus nanoplatelets with tuneable functionalities.…”