InGaN based resonant-cavity light-emitting diode (RC-LED) structures with an embedded porous-GaN/n-GaN distributed Bragg reflector (DBR) and a top dielectric Ta₂O₅/SiO₂ DBR were demonstrated. GaN:Si epitaxial layers with high Si-doping concentration (n⁺-GaN:Si) in the 20-period n⁺-GaN/n-GaN stacked structure were transformed into a porous-GaN/n-GaN DBR structure through the doping-selective electrochemical wet etching process. The central wavelength and reflectivity were measured to be 434.3 nm and 98.5% for the porous DBR and to be 421.3 nm and 98.1% for the dielectric DBR. The effective 1λ cavity length at 432nm in the InGaN resonant-cavity consisted of a 30 nm-thick Ta₂O₅ spacer and a 148 nm-thick InGaN active layer that was analyzed from the angle-resolved photoluminescence (PL) spectra. In the optical pumping PL spectra, non-linear emission intensity and linewidths reducing effect, from 6.5 nm to 0.7 nm, were observed by varying the laser pumping power. Directional emission pattern and narrow linewidth were observed in the InGaN active layer with bottom porous DBR, top dielectric DBR, and the optimum spacer layer to match the short cavity structure.

In this study, ZnO/ZnS nanocomposite-based dual UV light/CO gas sensing devices have been demonstrated for the first time. To characterize the nanocomposites, multiple material characterizations indicated ZnS/ZnO core-shell rods were successfully formed on SiO ₂ substrates. Moreover, CO gas sensing and UV light detection measurements both revealed that incorporation of a ZnS shell on ZnO nanorods (NRs) can effectively increase gas sensing and light detection capabilities. Owing to their compact size, low cost, and simple fabrication, ZnO/ZnS NR-based gas and light dual-sensing devices show promises in hazardous gas and light monitoring.

Magnesium oxide (MgO) sensing membranes in pH-sensitive electrolyte-insulator-semiconductor structures were fabricated on silicon substrate. To optimize the sensing capability of the membrane, CF₄ plasma was incorporated to improve the material quality of MgO films. Multiple material analyses including FESEM, XRD, AFM, and SIMS indicate that plasma treatment might enhance the crystallization and increase the grain size. Therefore, the sensing behaviors in terms of sensitivity, linearity, hysteresis effects, and drift rates might be improved. MgO-based EIS membranes with CF₄ plasma treatment show promise for future industrial biosensing applications.

The high- <mml:math display="inline"><mml:mi>k</mml:mi></mml:math>k <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Gd</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Gd2O3 films deposited on polycrystalline silicon treated with different post rapid thermal annealing (RTA) temperatures were formed as high- <mml:math display="inline"><mml:mi>k</mml:mi></mml:math>k interdielectrics. A combinational electrical and material analysis on the samples was performed to obtain a thorough understanding of annealing effect on the high- <mml:math display="inline"><mml:mi>k</mml:mi></mml:math>k <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Gd</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Gd2O3 interdielectrics. The annealing temperature at <mml:math display="inline"><mml:mrow><mml:mn>900</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>900°C was the optimal condition to reduce the defects and interface traps and hence improve material quality to fabricate a well-crystallized film. This high- <mml:math display="inline"><mml:mi>k</mml:mi></mml:math>k <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Gd</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>Gd2O3 interdielectric shows promise for future generation of nonvolatile memory applications.

We report here a simple and robust process to convert periodic Si-doped GaN/undoped-GaN epitaxial layers into a porous-GaN/u-GaN distributed Bragg reflector (DBR) structure and demonstrate its material properties in a high-reflectance epitaxial reflector. Directional pipe-GaN layers with anisotropic optical properties were formed from n⁺-GaN : Si layers in a stacked structure through a lateral and doping-selective electrochemical etching process. Central wavelengths of the polarized reflectance spectra were measured to be 473 nm and 457 nm for the pipe-GaN reflector when the direction of the linear polarizer was along and perpendicular to the pipe-GaN structure. The DBR reflector with directional pipe-GaN layers has the potential for a high efficiency polarized light source and vertical cavity surface emitting laser applications.