High-quality-factor tantalum oxide nanomechanical resonators by laser oxidation of TaSe2

Abstract

Controlling the strain in two-dimensional materials is an interesting avenue to tailor the mechanical properties of nanoelectromechanical systems. Here we demonstrate a technique to fabricate ultrathin tantalum oxide nanomechanical resonators with large stress by laser-oxidation of nano-drumhead resonators made out of tantalum diselenide (TaSe2), a layered 2D material belonging to the metal dichalcogenides. Prior to the study of their mechanical properties with a laser interferometer, we checked the oxidation and crystallinity of the freely-suspended tantalum oxide in a high-resolution electron microscope. We show that the stress of tantalum oxide resonators increase by 140 MPa (with respect to pristine TaSe2 resonators) which causes an enhancement of quality factor (14 times larger) and resonance frequency (9 times larger) of these resonators.allows size reduction. For low-noise operation of nanomechanical systems it is desirable to achieve high quality factors Q at high frequencies. In conventional nanomechanical systems, based on silicon nitride (Si3N4) beams, it has been shown that both f0 and Q can be enhanced by increasing the stress in the beam [1,2]. For this purpose, several methods have been proposed to tune the stress in nanomechanical systems based on 2D materials using temperature, mechanical actuators and gas pressure [3][4][5][6]. For permanent stress modification in polycrystalline graphene, a method for direct bonding between graphene platelets has been proposed [6].

Mechanical characterization and cleaning of CVD single-layer h-BN resonators

“…34 The reflected red light is captured by a high speed photo-detector (NewFocus 1601) whose signal is crossed with the driving signal of the diode laser connected to a network analyzer (Rohde & Schwartz, ZVB4). The measurements are carried out in vacuum (10 −6 mbar) for room temperature measurements, and higher vacuum when cooling.…”

“…[30][31][32] Mechanical devices made out of 2D materials are often fabricated with a polymer-assisted transfer technique that requires a wet release of the suspended system, 4,8,29 or a dry method that exploits the viscoelastic properties of polydimethylsiloxane (PDMS). 33,34 In the case of drum devices where the membrane seals a cavity of a few hundreds of nanometers in depth, a dry transfer is more convenient as surface forces caused by liquid menisci upon drying tend to break the structure or push it to the bottom of the cavity resulting in collapsed devices.…”

Tunable Photodetectors via In Situ Thermal Conversion of TiS3 to TiO2

“…Moreover, lattice vacancies and atomic-level defect combined with the presence of light can accelerate the oxidation process [4][5][6][7][8], which is typically accompanied by a degradation of the electrical and optical properties reducing the device performance [9][10]. Furthermore, shining high intensity light on 2D materials can induce additional processes of photo-oxidation [11][12][13][14]. The overall performance reduction induced by oxidation seems to be one of the main issues to solve in developing industrial applications based on 2D materials, therefore controlling the oxidation process is a very active subject for both fundamental and applied research in the context of band engineering.…”

Mechanical properties of Bi2Te3 topological insulator investigated by density functional theory and nanoindentation

“…The study of mechanical properties is crucial for designing many technological applications as nanoelectromechanical systems (NEMS) [24,25] and flexible electronic devices [26] and, moreover, for the promising prospect of TI-based mechanical metamaterials [27]. However, the comprehension of mechanical properties of TIs is still unsatisfactory.…”