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The performances of nitrogen dioxide (NO2) gas sensors using various dimensional tantalum pentoxide-alloyed indium oxide (Ta:In2O3) rod arrays were investigated, in which the rod arrays were patterned by a laser interference photolithography system. The rod number amount and the surface area-to-volume ratio increased with a decrease of the period of rod array. The best responsivity of 76.1 and the lower operation temperature of 110 °C for the NO2 gas sensors using the sensing membranes of 0.6- $\mu \text{m}$ -periodic Ta:In2O3 rod array were obtained. Besides, the limiting sensing concentration of 0.7 ppm could be detected using the associated NO2 gas sensors. Furthermore, the response time and the recovery time were respectively reduced to 48 s and 329 s, respectively, when the NO2 gas sensors operated at 110 °C under NO2 gas concentration of 100 ppm.

In this paper, various tantalum pentoxide-alloyed indium oxide (Ta:In2O3) films were deposited on quartz substrates as the sensing membranes of nitrogen dioxide (NO2) gas sensors using a radio-frequency (RF) magnetron co-sputte-ring system. Using an energy-dispersive spectrometer (EDS), the Ta content in the deposited Ta:In2O3 films was 0, 1.28, 2.33, and 2.98 at.% corresponded to the RF power of 0, 30.0, 37.5, and 45.0 W applied to the tantalum pentoxide (Ta2O5) target, respectively. The grain size of the Ta:In2O3 films calculated from the X-ray diffraction (XRD) results was reduced from 9.9 to 7.6 nm as the Ta content of the Ta:In2O3 films increased from 0 to 2.98 at.%. The associated electron concentration increased from $1.9\times 10^{16}$ cm $^{-3}$ to $1.0\times 10^{18}$ cm $^{-3}$ by increasing the Ta content from 0 to 2.33 at.%. Compared with the indium oxide (In2O3) gas sensors, since the Ta:In2O3 sensing membrane with the Ta content of 2.33 at.% had the lowest activation energy of 0.39 eV, its responsivity was enhanced from 29.8 to 64.5 and the operation temperature was decreased from 150 °C to 120 °C under a NO2 concentration of 100 ppm. Under a NO2 concentration of 100 ppm at an operation temperature of 120 °C, the associated response time and recovery time of the Ta:In2O3 gas sensor with a Ta content of 2.33 at.% were improved to 59 and 339 s, respectively.

To improve the conversion efficiency of InGaP/InGaAs/Ge triple-junction solar cells, AuGeNi/Au nanomesh electrode structure and TiO2 nanostructured antireflection structure were designed and fabricated. Laser interference photolithography system was used to pattern 330-nm-wide nanomesh electrode structures with various AuGeNi/Au metal line intervals. Oblique evaporation method using electron beam evaporator was used to deposit TiO2 nanorod arrays with various periods. By using the AuGeNi/Au nanomesh electrode structure with metal line interval of 100 μm, the conversion efficiency of the InGaP/InGaAs/Ge triple-junction solar cells was improved to 35.25% compared with 30.84% of that with conventional bus-bar electrode structure. By using the TiO2 nanorod array with a period of 1.00 μm to replace the TiO2/SiO2 antireflection structure, the conversion efficiency was further improved from 35.25% to 37.00%.

This study applied a vapor cooling condensation system for depositing p-ZnO:LiNO3, i-Ga2O3, and n-Ga2O3:Si layers on sapphire substrates to fabricate solar-blind p-i-n deep-ultraviolet photodetectors (DUV-PDs). The deposited i-Ga2O3 absorption layer was measured to exhibit high performance levels. Therefore, when the resulting solar-blind p-i-n DUV-PDs were operated at a reverse bias voltage of − 5 V, the dark current and the DUV (250 nm)/visible (500 nm) rejection ratio were 1.45 pA and 2.5 × 104, respectively. Moreover, when the solar-blind p-i-n DUV-PDs were operated at a reverse bias voltage of − 5 V, the photoresponsivity, noise power density, noise equivalent power, and specific detectivity were 0.73 A/W, 2.45 × 10−26 A2/Hz, 4.80 × 10−13 W, and 1.97 × 1012 cmHz0.5W−1, respectively. Furthermore, flicker noise was the dominant low-frequency noise source in the photodetectors. These results demonstrated the effectiveness of the proposed solar-blind p-i-n DUV-PDs.

This study investigated the sensitivity dependence of thin-film-structured NO2 gas sensors on the surface morphology of indium oxide-sensing membranes. The indium oxide-sensing membranes were deposited on quartz substrates by using a radio frequency magnetron sputtering system at various oxygen/(argon + oxygen) ratios to modify their In and O atomic percentage, surface morphology, and grain size in the membranes. According to the energy dispersive spectroscopy and x-ray diffraction results, the oxygen atomic percentage and the grain size of the indium oxide-sensing membranes increased and decreased with an increase in the oxygen/(argon + oxygen) ratio, respectively. Through atomic force microscopy, the average roughness of 50-nm-thick indium oxide films deposited at various ratios of oxygen/(argon + oxygen), namely 0% oxygen (pure argon), 20% oxygen, 60% oxygen, and 100% oxygen (pure oxygen), was found to be 0.80 nm, 0.98 nm, 2.68 nm, and 1.25 nm, respectively. The highest sensitivity of the various NO2 gas sensors was observed at an operating temperature of 150°C because of the generated $$ {\hbox{O}}^{ - } $$ ions and the provision of sufficient energy to overcome the required activation energy. At the operating temperature of 150°C, the sensitivity tendency of the various NO2 gas sensors was according to the surface roughness of the indium oxide-sensing membranes. Furthermore, the response and the recovery times of the various NO2 gas sensors corresponded to the surface morphology of the indium oxide-sensing membranes. The response and the recovery times of the NO2 gas sensors operated at 150°C under an NO2 gas concentration of 100 ppm were 70 s and 364 s, respectively.

The two-finger stacked bottom gate and top gate fin indium gallium zinc aluminum oxide thin-film transistors (IGZAO TFTs) were fabricated. Since the bottom induced channel layer and the top induced channel layer were formed in the stacked TFTs using the bottom gate and the top gate, simultaneously. Consequently, drain-source current and transconductance of the stacked TFTs were enhanced about twice as those of the bottom gate TFTs and the top gate TFTs. The optimal performances of the stacked TFTs could be obtained, when the whole channel layer was induced as the carrier transportation path.

To study the self-heating effect, aluminum oxide (Al2O3) barrier layers of various thicknesses have been inserted between the channel layer and insulator layer in bottom-gate-type indium gallium zinc aluminum oxide (IGZAO) thin-film transistors (TFTs). Each IGZAO channel layer was deposited on indium tin oxide (ITO)-coated glass substrate by using a magnetron radiofrequency cosputtering system with dual targets composed of indium gallium zinc oxide (IGZO) and Al. The 3s orbital of Al cation provided an extra transport pathway and widened the conduction-band bottom, thus increasing the electron mobility of the IGZAO films. The Al–O bonds were able to sustain the oxygen stability of the IGZAO films. The self-heating behavior of the resulting IGZAO TFTs was studied by Hall measurements on the IGZAO films as well as the electrical performance of the IGZAO TFTs with Al2O3 barrier layers of various thicknesses at different temperatures. IGZAO TFTs with 50-nm-thick Al2O3 barrier layer were stressed by positive gate bias stress (PGBS, at gate–source voltage V GS = 5 V and drain–source voltage V DS = 0 V); at V GS = 5 V and V DS = 10 V, the threshold voltage shifts were 0.04 V and 0.2 V, respectively, much smaller than for the other IGZAO TFTs without Al2O3 barrier layer, which shifted by 0.2 V and 1.0 V when stressed under the same conditions.

This article describes a high-efficiency light-induced dielectrophoresis biochip containing a thin film prepared through inductively coupled plasma chemical vapor deposition (ICPCVD). The biochip comprises two ITO glass substrates and a photoconductive amorphous silicon thin film. The biochip can effectively sort particular particles (or cells) by projecting visible light onto the surface of the silicon thin film. The sorting efficiency of biochips is highly associated with the quality of the deposited amorphous silicon thin films; therefore, the choice of deposition technique is extremely critical. However, no study has examined this problem. Hence, the current study thoroughly compared the efficiency of the biochip when films produced through plasma-enhanced chemical vapor deposition and ICPCVD are used.