This work investigates the impact of lateral scaling on the high-frequency characteristics of a β-Ga2O3 back-barrier (BB) HEMT incorporating a compositionally graded InAlN buffer. The proposed device structure consists of a sapphire substrate, graded InAlN buffer, β-Ga2O3 BB, GaN channel, and AlGaN barrier layer. The influence of LG and LGS on carrier confinement, electrical performance, and RF characteristics is systematically analysed. Energy band analysis reveals the formation of a deep quantum well at the heterointerface, facilitating strong 2DEG. The β-Ga2O3 BB effectively suppresses electron leakage toward the buffer region, while the graded InAlN buffer improves carrier transport through reduced scattering. The device exhibits a maximum drain current of approximately 2.4 A/mm at V_GS = 2 V for LG = 20 nm and a peak transconductance of about 1.55 S/mm. High-frequency analysis demonstrates a maximum fT of nearly 300 GHz for optimized LGS and 250 GHz for LG = 20 nm. Furthermore, reduced gate length significantly lowers parasitic capacitances, leading to enhanced RF performance. The results indicate that lateral scaling strongly influences carrier transport, electrostatic control, and frequency response, with gate-length scaling exhibiting a more pronounced effect than source-to-gate spacing variation. The proposed β-Ga2O3 back-barrier architecture with a graded InAlN buffer demonstrates considerable potential for microwave, millimeter-wave, and advanced RF applications.
This paper explores the application of Organic Thin-Film Transistors (OTFTs) sensors in their detection of tumor cells, with a specific focus on measuring Prostate-Specific Antigen (PSA) concentration, a critical biomarker for diagnose of prostate-cancer. The study emphasizes the importance of sensitivity and specificity in the OTFT sensor’s compare to digital rectal examination (DRE) performance, as these parameters are essential for accurate cancer diagnostics. Sensitivity ensures that the sensor can detect low PSA concentrations, which is crucial for early-stage detection, while specificity minimizes false positives, distinguishing between malignant and benign conditions effectively. The input characteristics of the OTFT sensor, particularly the gate voltage, play a significant role in its ability to detect PSA. Proper calibration of the gate voltage enhances the sensor’s sensitivity, enabling the detection of subtle changes in PSA levels. The output-characteristics, represented by the drain current, provide a quantifiable measure of PSA concentration, which is essential for assessing the presence and progression of tumour cells. This study demonstrates the potential of OTFT sensors as a non-invasive, precise, and reliable method for early cancer detection. By optimizing sensitivity, specificity, and the sensor’s input–output characteristics, OTFT technology could significantly improve diagnostic accuracy and patient outcomes in cancer care.
The development of sustainable nanomaterials with tunable electrical and dielectric properties is essential for next-generation electronic and functional device applications. In this work, mixed-phase iron oxide nanoclusters (Fe3O4/FeO) were synthesized via a green co-precipitation route using jojoba oil as a natural reducing and stabilizing agent under mild and environmentally friendly conditions. Structural characterization by FTIR, XRD, and SEM/EDX confirmed the formation of Fe–O bonds, organic surface capping, and the coexistence of magnetite (Fe3O4) and wüstite (FeO) phases. The synthesized nanoclusters exhibited nanoscale crystallinity and aggregated spherical morphology. Electrical investigations revealed two distinct frequency-dependent conduction mechanisms: localized hopping conduction at low frequencies and thermally activated variable-range hopping at higher frequencies. The activation energy increased progressively with frequency, indicating enhanced charge transport barriers at elevated frequencies. Dielectric measurements demonstrated pronounced temperature- and frequency-dependent behavior, with enhanced polarization and increased capacitance at higher temperatures. The observed electrical transport and dielectric characteristics highlight the suitability of the synthesized Fe3O4/FeO nanoclusters for dielectric, electronic, and charge-storage-related applications. These findings demonstrate that jojoba oil provides an effective and sustainable route for producing functional iron oxide nanomaterials with promising electrical performance.
This work presents a dual-gate Al0.23Ga0.77N/GaN MOSHEMT biosensor for the simultaneous detection of two significant CEA and HER2 cancer biomarkers. The proposed device employs two independently functionalized gate electrodes which enabling parallel sensing through a shared two-dimensional electron gas (2DEG) channel. The gates are laterally positioned and electrically separated by a 50 nm Al2O3 isolation gap which facilitates selective and multiplexed biomarker detection on a single platform. A bilayer dielectric stack of HfO2 and Al2O3 is utilized to minimize gate leakage current and enhance sensing capability. The device performance is analysed using Silvaco ATLAS TCAD simulations with appropriate polarization based physical models. The simulation results show that the CEA-functionalized gate exhibits a sensitivity of 1.06 × 10–6 A/µm per unit concentration. The biosensor achieves a sensitivity of 2.95 × 10–7 A/µm per unit concentration at a drain voltage of 10 V during simultaneous detection of HER2 and CEA. The proposed structure enables efficient multiplexed biomarker sensing on a single chip and demonstrates improved performance over traditional single gate HEMT biosensors.
In this work, vacuum electron acceleration driven by a periodic chirped Hermite–Sinh–Gaussian (HSG) laser pulse is theoretically investigated, with particular emphasis on the influence of frequency chirp parameters and beam waist on relativistic energy gain. The study demonstrates that frequency chirping significantly modifies the phase evolution of the electromagnetic field, thereby improving phase synchronism between the electron and the accelerating field. In the unchirped case, energy saturation occurs at 3.38 GeV due to rapid electron–laser dephasing. Introduction of a positive chirp enhances phase matching and prolongs the effective interaction time, leading to systematic energy enhancement. The saturation energy increases from 3.84 GeV (α = 0.002) to 4.18 GeV (α = 0.005). Similarly, the chirp modulation constant Ω plays a crucial role in dynamic frequency compensation, increasing the maximum energy to 4.18 GeV for Ω = 0.002. Furthermore, the beam waist is found to strongly influence acceleration efficiency. Larger beam waists reduce transverse ponderomotive effects, extend the interaction length, and enhance longitudinal confinement, resulting in a monotonic rise in energy up to 5.26 GeV. The results establish chirp parameters and beam waist as effective control parameters for optimizing vacuum electron acceleration.
