Impact of plasma treatment on graphene's transport properties and interaction with gas molecules has been investigated Raman, X-ray photoelectron spectroscopy, Hall measurements. Experimental results indicate the formation nanocrystalline domains enhanced fraction adsorbed oxygen following treatment, which correlates a significant reduction in carrier mobility an increase density. The treated graphene was found to exhibit much stronger sensitivity toward NH3 both terms magnitude response...

The UV detection capabilities of III-nitride dual channel triangular microcantilevers, consisting AlGaN/GaN two-dimensional electron gas channels with an intervening GaN layer, were investigated using 265, 315, and 375 nm illumination. High spectral responsivities, up to 2.3 × 104 A/W, observed along a very low dark current few pA, which resulted in detectivity 4.99 108 Jones. A high UV–visible rejection ratio was also measured between the wavelengths 265 450 nm. simple analysis...

A graphene-based ISFET has been developed and demonstrated high sensitivity direct measurement of K⁺ ion efflux from live cells.

Strong enhancement in a photoacoustic signal due to plasmonic absorption Au nanostructures was measured using piezotransistive GaN microcantilevers. A pulsed 790 nm laser focused on the metallization of piezotransistor resulted much larger compared non-metallized areas. Upon deposition 5 layer, increased significantly for both previously metallized and areas, while 2 Ni decreased signal, confirming role facilitating absorption. Infrared microscopy images covering boundary surfaces indicated...

Surface work function (SWF) measurements using a piezotransistive III–nitride cantilever has been demonstrated on multiple surfaces. The minimum detectable surface potential change of 10 mV was achieved with signal to noise ratio 3. This method applied determine the changes due exposure 5 ppm NO2 in graphene and In2O3 thin film, simultaneously conductivity changes. potentiometric yielded 100 80 SWFs respectively, which matches very well experimental data published earlier indicating efficacy...

Real-time toxic gas mapping in complex urban environments have become increasingly possible with improvements data analysis and network infrastructures. Hindering this is the cost operation requirements of commercial sensors, requiring sensors high sensitivity selectivity that are robust capable operating at room temperature. Transition metal oxide-based historical significance production due to their low target gases. The inherent conductivity oxides, however, requires temperatures higher...

Detection of H2 using plasmonic amplification surface photoacoustic (SPA) waves generated in Pd nanoparticle-deposited GaN piezotransistive microcantilevers has been investigated a pulsed 520 nm laser. Using 1.5 thickness the functionalization layer, detection down to ppm was demonstrated with high signal-to-noise ratio, underscoring feasibility sub-ppm level this novel sensing method. Adsorption nanoparticles (NPs) changes their absorption spectra because lattice expansion, addition...

Abstract Nonlinear oscillations in micro- and nanoelectromechanical systems have emerged as an exciting research area recent years due to their promise realizing low-power, scalable, reconfigurable mechanical memory logic devices. Here, we report ultralow-power operations utilizing the nonlinear oscillation regime of GaN microcantilevers with embedded piezotransistive AlGaN/GaN heterostructure field effect transistors highly sensitive deflection transducers. Switching between high low...

For the first time, dynamic response of GaN microcantilevers with integrated piezoresistive VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mesa, as high sensitive deflection transducers have been investigated. The studies are carried out by a direct excitation method using piezo-chip attached to bottom microcantilever structure, highlighting utility these cantilevers transducers. phase was able detect acoustic waves generated in Si...

Development of compact and fast modulators infrared light has garnered strong research interests in recent years due to their potential applications communication, imaging, sensing. In this study, electric field induced modulation near-infrared caused by phase change VO 2 thin films grown on GaN suspended membranes been reported. It was observed that metal insulator transition temperature or application field, using an interdigitated finger geometry, resulted 7% 14% reduction transmitted...

Epoxy is one of the options for packaging graphene based chemical and bio-sensors. In this work, effect epoxy its curing agent on electrical characteristics field transistor investigated. A Dirac point shift 36 V was observed after 2 hours exposure, while 15 minutes exposure changed more than 130V, from 63 to −68 V, completely changing doping type strong p-type n-type due electron donating nature adsorbed molecules. The significant change in electronic properties amine group present agent.

In this work, a highly sensitive photoacoustic (PA) based detection of analytes has been demonstrated using GaN microcantilevers coated with thin layer metal nanoparticles (NPs). Microcantilevers were oscillated at their resonance frequencies by PA excitation generated from pulsed 520 nm laser, whose amplitude was enhanced the plasmonic absorption in NPs. Analytes such as Hg vapor and H2 altered properties specific NPs, resulting change photons hence difference signal strength. Changes is...

We have investigated nonlinear dynamic characteristics of piezotransistive GaN microcantilevers, with integrated AlGaN/GaN heterostructure field effect transistor as a highly sensitive deflection transducer. When excited piezochip actuator, both softening and hardening type behavior were exhibited by the microcantilevers in their first flexural mode. The was found to strongly depend on dimensions these microcantilevers. While be enhanced increase length cantilever for fixed width, changed...

P(VDF-TrFE)-based piezoelectric materials have attracted interest in recent years due to their application energy harvesting systems. However, the fabrication process is still complicated and less durable for long-term vibrational motion. Here, we demonstrated a highly flexible P(VDF-TrFE) film-based self-powered harvester on PDMS substrate with simple structure high sensitivity. This can produce ~11.7 V (maximum peak value), 3.6 (average value) provides power density of 2.35 nW/cm <sup...

Photoacoustic (PA) detection of H2 and NH3 using plasmonic excitation in Pt- Pd-decorated GaN piezotransistive microcantilevers were investigated pulsed 520-nm laser illumination. The sensing performances 1-nm Pt Pd nanoparticle (NP) deposited cantilever devices compared, which the Pd-coated sensor exhibited consistently better performance, with lower limit superior signal-to-noise ratio (SNR) values, compared to Pt-coated devices. Among two functionalization layers, found respond only...

AlGaN/GaN based heterostructures have attracted significant research interests in recent years for sensing very small scale displacement utlizing their unique piezoelectric properties. heterojunction Field Effect Transisitors (HFETs), when embedded at the base of a GaN cantilever, can be utilized to transduce with much higher Gauge Factor (GF) than Si counterparts, by using polarization induced change two dimensional electron gas density interface [1][2]. Specifically, detection femtometer...

AlGaN/GaN Heterojunction Field Effect Transistor (HFET) embedded GaN piezotransistive microcantilevers are used as potentiometric sensors. 10mV potential difference between the cantilever tip and a metal electrode is successfully measured at resonance frequency. Moreover, quality factor enhancement of low pressure demonstrated.

VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film was incorporated with GaN microcantilevers, and proved to be highly sensitive detector detect acoustic waves at resonance frequency, but the not of very high quality. In order produce quality mesa used for thin films were synthesized using low pressure chemical vapor deposition technique (LPCVD) on AlGaN/GaN epitaxial layer Si (111) substrate, characterized X-ray diffraction (XRD)...

The static and dynamic deflection transducing performances of piezotransistive AlGaN/GaN heterojunction field effect transistors (HFET) piezoresistive VO2 thin films, fabricated on GaN microcantilevers similar dimensions, were investigated. Deflection sensitivities tuned with the gate bias operating temperature for embedded HFET film transducers, respectively. excited a piezoactuator in their linear nonlinear oscillation regions fundamental oscillatory mode. In regime, maximum sensitivity...

The sharp transition in electrical and structural properties of Vanadium dioxide during the Metal-Insulator Transition (MIT) is highly attractive for various electronic, optoelectronic sensing applications. In this work, we have studied Chemical Vapor Deposition based synthesis VO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> on Gallium Nitride (GaN) thin films compared them with those synthesized Silicon Sapphire. Thin film vanadium...

In this work, we present the nonlinear dynamic characteristics of AlGaN (20 nm, 25% Al)/GaN HFET embedded self-sensing GaN microcantilevers oscillated using a piezochip actuator. For first bending mode, Euler-Bernoulli beam theory predicts dominance hardening behavior regardless cantilever dimensions. However, both softening and type nonlinearities have been observed in flexural mode with dimensions (length x width) 250×90, 250×100, 150×50 300×50 μm <sup...

In the recent years, microcantilevers with promising deflection sensitivities have been extensively studied in numerous applications including gas sensors. this study, NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> detection experiment has demonstrated via piezotransistive GaN utilizing Kelvin probe measurement technique which is based on electrostatic force between cantilever tip and O...

In this work, we have studied the plasmonic absorption of different metal nanoparticles (NP) in visible and near infrared (NIR) range using a unique photoacoustic (PA) detection technique utilizing piezotransistive GaN microcantilevers. To investigate interaction NPs, three (Au, Ni Pt) NPs two laser wavelengths (520 nm 790 nm) were used. The lasers are pulsed to generate PA excitation that oscillates cantilever deflection is then transduced by an HFET at base cantilever. Au Pt showed...