Session Index

Gallium nitride semiconductors are gaining prominence in high-frequency and high-power applications due to their wide bandgap, high electron velocity, high breakdown field, and excellent thermal conductivity. Among these, trench gate metal-oxide-semiconductor field-effect transistors are particularly promising due to their manufacturability without epi-material regrowth or ion implantation . However, dry etching for trench definition damages the sidewalls, affecting device performance. Sidewall treatment is crucial, with methods like tetramethylammonium hydroxide (TMAH) and H3PO4 being explored for defect mitigation. This study compares the effects of TMAH and H3PO4 treatments on the threshold voltage (VTH) and current density, revealing significant differences in device performance.

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In this study, MoS₂ was grown on laser-processed sapphire substrates with periodic arrays of holes using chemical vapor deposition (CVD), aiming to investigate its growth mechanism on substrates featuring periodic structures. Raman spectroscopy, photoluminescence spectroscopy, and atomic force microscopy were employed to characterize the distribution of MoS₂ layer numbers, while transmission electron microscopy (TEM) was used to further study its growth mechanism. Experimental results demonstrate that MoS₂ was successfully grown on substrates with periodic holes under suitable conditions. This work provides a useful reference for large-area periodic growth of MoS₂

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A low-cost Cu2O-based biosensor was fabricated using electrochemical deposition and integrated with zigzag-shaped interdigitated electrodes. The device enables photoelectrochemical and impedance analysis of three lung cancer cell lines.Results show a strong linear correlation between cell concentration and both photocurrent and admittance changes. This sensor demonstrates potential for early lung cancer diagnosis through label-free, electrical and optical detection.

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We investigated the surface Fermi level pinning characteristics of (10-11) n-GaN surfaces by employing Schottky diodes with different metals. As the temperature increases, Schottky barrier heights (SBH) increases linearly and ideality factors decreases. This behavior is related to the barrier height inhomogeneity. Inhomogeneity-model based SBHs are evaluated to be dependent on the metal work functions (WF) and are similar to those measured from capacitance-voltage relation. The S-parameter, d(SBH)/d(WF), indicates the partial pinning of the surface Fermi level at the surface states below the conduction band. Tetramethyl ammonium hydroxide (TMAH)-treatment effectively passivates the surface, reducing pinning behaviour.

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Positron annihilation spectroscopy has been used rather extensively to study vacancy-type defects in nitride semiconductors. This contribution gives an overview of the most recent results, and discusses the role of vacancy defects in determining the optical and electrical characteristics of the various materials, as well as related open questions.

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