Ultrawide Band Gap β-Ga₂O₃ Nanomechanical Resonators with Spatially Visualized Multimode Motion

Abstract

Beta gallium oxide (β-GaO) is an emerging ultrawide band gap (4.5 eV-4.9 eV) semiconductor with attractive properties for future power electronics, optoelectronics, and sensors for detecting gases and ultraviolet radiation. β-GaO thin films made by various methods are being actively studied toward such devices. Here, we report on the experimental demonstration of single-crystal β-GaO nanomechanical resonators using β-GaO nanoflakes grown via low-pressure chemical vapor deposition (LPCVD). By investigating β-GaO circular drumhead structures, we demonstrate multimode nanoresonators up to the sixth mode in high and very high frequency (HF/VHF) bands, and also realize spatial mapping and visualization of the multimode motion. These measurements reveal a Young's modulus of E = 261 GPa and anisotropic biaxial built-in tension of 37.5 MPa and 107.5 MPa. We find that thermal annealing can considerably improve the resonance characteristics, including ∼40% upshift in frequency and ∼90% enhancement in quality (Q) factor. This study lays a foundation for future exploration and development of mechanically coupled and tunable β-GaO electronic, optoelectronic, and physical sensing devices.

Hydrogel Microelectromechanical System (MEMS) Resonators: Beyond Cost‐Effective Sensing Platform

“…Besides manufacturability and stability, silicon-based materials such as single crystal silicon [6] and stress-controlled silicon nitride [7,8] also offer a high-quality factor preferred for high-resolution mass sensing applications. [11][12][13] One of the promising alternative candidate materials for MEMS resonators is polymer, a large molecule composed of many repeated subunits. [10] It is clear that material requirements for stable oscillators and sensors are quite different and even contradictory.…”

“…Therefore, many researchers have been naturally seeking alternative materials to make resonators used for sensing applications. [11][12][13] One of the promising alternative candidate materials for MEMS resonators is polymer, a large molecule composed of many repeated subunits. A variety of polymeric materials have been employed to make a microcantilever (singly clamped or clamped-free beam), a typical MEMS resonator.…”

Gallium and Indium Alkoxides with Hydride, Cyclopentadienediide and Copper(I) tert‐Butoxide as further Components

“…Materials based on oxides of gallium and indium have since several years attracted high attention due to their use in advanced physics: so β ‐Ga 2 O 3 is actually studied as a wide bandgap semiconductor or for use as ultra‐high power rectifier . Indium oxide since many years is used as basic material for TCOs (Transparent Conducting Oxides) especially in combination with other metal oxides .…”

<inline-formula> <tex-math notation="LaTeX">$\beta$ </tex-math> </inline-formula>-Ga2O3 NEMS Oscillator for Real-Time Middle Ultraviolet (MUV) Light Detection

“…[14]. We fabricate suspended β-Ga 2 O 3 nanomechanical structures from β-Ga 2 O 3 nanoflakes by using a dry transfer technique [9]. Fig.…”