For the creation of next-generation nanoscale devices, it is crucial to comprehend the carrier transport mechanisms in nanowires. Here, we examine how temperature affects the properties of GaN nanowire wrap-gate transistors (WGTs), which are made via a top-down technique. The predicted conductance in this transistor remains essentially unaltered up to a temperature of 240 K and then increases after that as the temperature rises. This is true for increasing temperature at gate voltages less than threshold voltage (Vgs < Vth). Sharp fluctuations happen when the temperature rises with a gate voltage of Vth < Vgs < VFB. The conductance steadily decreases with increasing temperature after increasing the gate bias to Vgs > VFB. These phenomena are possibly attributed to phonon and impurity scattering processes occurring on the surface or core of GaN nanowires.
It is essential to understand the barrier height, ideality factor, and role of inhomogeneities at the metal/semiconductor interfaces in nanowires for the development of next generation nanoscale devices. Here, we investigate the drain current (Ids)–gate voltage (Vgs) characteristics of GaN nanowire wrap-gate transistors (WGTs) for various gate potentials in the wide temperature range of 130–310 K. An anomalous reduction in the experimental barrier height and rise in the ideality factor with reducing the temperature have been perceived. It is noteworthy that the variations in barrier height and ideality factor are attributed to the spatial barrier inhomogeneities at the AlGaN/GaN interface in the GaN nanowire WGTs by assuming a double Gaussian distribution of barrier heights at 310–190 K (distribution 1) and 190–130 K (distribution 2). The standard deviation for distribution 2 is lower than that of distribution 1, which suggests that distribution 2 reflects more homogeneity at the AlGaN/GaN interface in the transistor’s source/drain regions than distribution 1.
In recent years, there has been growing interest in the development of metal-free, environmentally friendly, and cost-effective biopolymer-based piezoelectric strain sensors (bio-PSSs) for flexible applications. In this study, we have developed a bio-PSS based on pure deoxyribonucleic acid (DNA) and curcumin materials in a thin-film form and studied its strain-induced current-voltage characteristics based on piezoelectric phenomena. The bio-PSS exhibited flexibility under varying compressive and tensile loads. Notably, the sensor achieved a strain gauge factor of 407 at an applied compressive strain of −0.027%, which is 8.67 times greater than that of traditional metal strain gauges. Furthermore, the flexible bio-PSS demonstrated a rapid response under a compressive strain of −0.08%. Our findings suggest that the proposed flexible bio-PSS holds significant promise as a motion sensor, addressing the demand for environmentally safe, wearable, and flexible strain sensor applications.
12 September 2023 in International Journal of Energy Research
The growth of one-dimensional (1D) ZnO systems has been attaining ample engrossment because of their unique photocatalytic and optoelectronic properties. In this context, we synthesized the high-quality ZnO and ZnO:Er nanorods through an inexpensive and facile solvothermal route. Morphological studies revealed that the fabricated samples correspond to nanorods. Erbium ion substitution into the host ZnO matrix was affirmed via XRD and Raman analyses. XPS analysis proposed that Er ion substitution in the Zn (II) site occurred with trivalent Er ions. The trivial diminishing of the optical band gap with the incorporation of Er into the host matrix was assessed by diffuse reflectance spectroscopy (DRS) studies. The photoluminescence spectra of both fabricated NRs display two nodes at ultraviolet and red luminescence. The fluorescence efficiency of the ZnO NRs diminished after Er doping. The ZnO and ZnO:Er NRs were measured for H2 evolution by water splitting beneath the UV light illumination. The ZnO:Er illustrated the efficient H2 evolution ability (21311μmolh−1g−1) in 5h, which is higher than that of ZnO. To analyze the attained engrossing H2 outcomes, electrochemical studies were also employed. Fortunately, this is the first-ever endeavor in H2 production of the ZnO:Er NRs.
We used capacitance–voltage (C–V), conductance–voltage (G–V), and noise measurements to examine the carrier trap mechanisms at the surface/core of an AlGaN/GaN nanowire wrap-gate transistor (WGT). When the frequency is increased, the predicted surface trap density promptly drops, with values ranging from 9.1 × 1013 eV−1∙cm−2 at 1 kHz to 1.2 × 1011 eV−1∙cm−2 at 1 MHz. The power spectral density exhibits 1/f-noise behavior in the barrier accumulation area and rises with gate bias, according to the 1/f-noise features. At lower frequencies, the device exhibits 1/f-noise behavior, while beyond 1 kHz, it exhibits 1/f2-noise behavior. Additionally, when the fabricated device governs in the deep-subthreshold regime, the cutoff frequency for the 1/f2-noise features moves to the subordinated frequency (~102 Hz) side.
Al-Cu thin films were fabricated by RF magnetron sputtering from aluminum (Al) and copper (Cu) metal targets to improve the acoustic performance of SAW devices on LiNbO3 substrates. To optimize the electrode material for SAW devices, Al-Cu films with various compositions were fabricated and their electrical, mechanical, and acoustic properties were comprehensively evaluated. The Al-Cu films exhibited a gradual decrease in resistivity with increasing Al content. The double-electrode SAW devices composed of Al-Cu films demonstrated a resonant frequency of 70 MHz and an average insertion loss of −16.1 dB, which was significantly lower than that of devices made with traditional Au or Al electrodes. Additionally, the SAW devices showed an increase in the FWHM values of the resonant frequency and a decrease in the insertion loss as the Al content in the IDT electrode decreased. These findings indicate that improving the performance of SAW devices can be achieved by reducing the density of the IDT electrodes, rather than focusing solely on their electrical characteristics.