This study demonstrates the fabrication and characterization of chicken egg albumen-based bio-memristors. By introducing egg albumen as an insulator to fabricate memristor devices comprising a metal/insulator/metal sandwich structure, significant bipolar resistive switching behavior can be observed. The 1/f noise characteristics of the albumen devices were measured and results suggested that their memory behavior results from the formation and rupture of conductive filaments. Oxygen diffusion and electrochemical redox reaction of metal ions under a sufficiently large electric field are the principal physical mechanisms of the formation and rupture of conductive filaments; these mechanisms were observed by analysis of the time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resistance–temperature (R–T) measurement results. The switching property of the devices remarkably improved by heat-denaturation of proteins; reliable switching endurance of over 500 cycles accompanied by an on/off current ratio (I_on/off) of higher than 10³ were also observed. Both resistance states could be maintained for a suitably long time (>10⁴ s). Taking the results together, the present study reveals for the first time that chicken egg albumen is a promising material for nonvolatile memory applications.

The depth-profiling XPS spectra results are strong evidence that the resistive switching effects are applicable to oxygen vacancy-based conductive mechanisms.

In this study, pH sensors were successfully fabricated on a fluorine-doped tin oxide substrate and grown via hydrothermal methods for 8 h for pH sensing characteristics. The morphology was obtained by high-resolution scanning electron microscopy and showed randomly oriented flower-like nanostructures. The TiO₂ nanoflower pH sensors were measured over a pH range of 2–12. Results showed a high sensitivity of the TiO₂ nano-flowers pH sensor, 2.7 (μA)^1/2/pH, and a linear relationship between I_DS and pH (regression of 0.9991). The relationship between voltage reference and pH displayed a sensitivity of a 46 mV/pH and a linear regression of 0.9989. The experimental result indicated that a flower-like TiO₂ nanostructure extended gate field effect transistor (EGFET) pH sensor effectively detected the pH value.

In this paper, amorphous indium-gallium-oxide solar-blind metal-semiconductor-metal photodetectors were fabricated by using co-sputtering method. Three samples with different oxygen concentrations, namely, sample A without oxygen, sample B with 2% oxygen concentration, and sample C with 4% oxygen concentration, were investigated. The applied bias was 5 V during device characterization. The ultraviolet (UV)-to-visible rejection ratios were 39, 9.9 x 10³, and 1.1 x 10⁷ for samples A, B, and C, respectively. The dynamic responses of the decay times were 5.79/52.12 s, 1.96/30.49 s, and 0.02/0.75 s for samples A, B, and C, respectively. In summary, the 4% oxygen concentration sample exhibited excellent UV-to-visible rejection ratio and superior decay time.

Gallium nitride $p\text{-}i\text{-}n$ ultraviolet photodiodes with low-temperature (LT)-GaN interlayer have been fabricated. It was found that the dark current of photodiode with LT-GaN interlayer is as small as $143\mathrm{pA}$ at $5\mathrm{V}$ reverse bias. It was also found that the responsivity of the photodiode with LT-GaN interlayer can be enhanced at a small electric field $(\sim 0.4\mathrm{MV}∕\mathrm{cm})$ due to the carrier multiplication effect. The UV photocurrent gain of 13 and large ionization coefficient $(\alpha =3.1\times {10}^5{\mathrm{cm}}^{-1})$ were also observed in the detector with LT-GaN interlayer. Furthermore, we can achieve a large peak responsivity of $2.27\mathrm{A}∕\mathrm{W}$ from the photodiode with LT-GaN interlayer.

In this letter, a compact and high performance parallel coupled line wideband bandpass filter (PCL-WBF) with open stubs is designed and implemented on the commercial substrate, RT/Duroid 5880. The PCL-WBF is composed of a one-stage coupled line and two open stubs connected near the input/output ports. The design procedure and limit are discussed in detail. The designed filter was fabricated and measured, showing good characteristics of wide stopband and very high passband selectivity. Measured results also have a good agreement with the simulated results.