Giant Piezoresistive On/Off Ratios in Rare-Earth Chalcogenide Thin Films Enabling Nanomechanical Switching

Abstract

Sophisticated microelectromechanical systems for device and sensor applications have flourished in the past decade. These devices exploit piezoelectric, capacitive, and piezoresistive effects, and coupling between them. However, high-performance piezoresistivity (as defined by on/off ratio) has primarily been observed in macroscopic single crystals. In this Letter, we show for the first time that rare-earth monochalcogenides in thin film form can modulate a current by more than 1000 times due to a pressure-induced insulator to metal transition. Furthermore, films as thin as 8 nm show a piezoresistive response. The combination of high performance and scalability make these promising candidates for nanoscale applications, such as the recently proposed piezoelectronic transistor (PET). The PET would mechanically couple a piezoelectric thin film with a piezoresistive switching layer, potentially scaling to higher speeds and lower powers than today's complementary metal-oxide-semiconductor technology.

Quantum strain sensor with a topological insulator HgTe quantum dot

“…Here we describe a novel strain sensor based on a strain-driven transition from a HgTe quantum dot with inverted bandstructure and robust topologically protected quantum edge states to a normal state without edge states in the energy gap. The presence/absence of edge states is expected to lead to large on/off ratio of conductivity across the quantum dot in analogy to recently demonstrated large piezoresistive current on/off ratios driven by a pressure-induced metal/insulator transition in rare earth chalcogenide thin films8. The electronic properties of a HgTe quantum dot as a function of applied strain are described using eight-band theory and surface states are identified with chirality of Luttinger spinors.…”

Rare‐earth‐incorporated low‐dimensional chalcogenides: Dry‐method syntheses and applications

“…C‐G, TEM images of the α‐Sm 2 S 3 nanowire bundle: C, TEM image of a separated α‐Sm 2 S 3 wire; D, SAED of the α‐Sm 2 S 3 wire at the selected area shown in C; E, High‐resolution TEM (HRTEM) image of the wire; F, crystal structure from the [001] view direction built by extended CrystalMaker; G, the simulated SAED spectra based on the crystal orientation indicated in F . Copyright 2013, Elsevier B.V. H‐K, Structural characterization of the SmSe thin films: H‐I, AFM images of 50 and 8 nm thick films; J‐K, TEM images of 50‐ and 8‐nm SmSe films . Copyright 2013, American Chemical Society.…”

“…Sputtering is the process in which particles are bombarded onto a solid surface to allow atoms or molecules near the surface to escape from the solid surface. RECs have been synthesized as the host of thin films by the sputtering method . As shown in Figure ‐K, SmSe thin films have been fabricated by the cosputtering process of Sm and Se at different temperatures .…”

“…RECs have been synthesized as the host of thin films by the sputtering method . As shown in Figure ‐K, SmSe thin films have been fabricated by the cosputtering process of Sm and Se at different temperatures . The effects of growth conditions on the crystallinity of SmSe is striking, such as the narrower peaks of growth at 300°C compared to deposition at room temperature.…”

Compact nanomechanical plasmonic phase modulators

“…Furthermore, non-plasmonic nanomechanical cantilever devices of similar dimensions have been made operating up to 1GHz with careful material choice, 30,31 and such a fast, yet ultrasmall modulator can potentially operate at low voltage with the use of piezoelectric actuation. [32][33][34] Considering the negligible power dissipation of its electrostatic-drive, actuation voltages at the level of the smallest high speed transistors, its length scale and feature size at the level of CMOS metallization layers, its broadband optical operation and its reasonable speed, we argue 9 that a GPPM can play a unique and important role as a building block for optoelectronic integration. A device with these features is particularly well suited as an element for on chip reconfigurable switch fabrics for future dynamic inter-and intra-chip optical communication architectures.…”