Dual gate material (Au and Pt) based double-gate MOSFET for high-speed devices

Aluminium Gallium Arsenide (AlGaAs) is a semiconductor material used in the latest design of double heterostructure laser diodes. This semiconductor is mostly available in the arbitrary alloy form between Gallium Arsenide and Aluminium Arsenide. It is derived from the Tri-MethylGallium (TMG/TMGa), and Arsine (AsH3), both the chemicals are pyrophoric and toxic. The resistance is less between source and drain contacts in the case of AlGaAs so that it has been proposed as a material to grow contacts on Indium Phosphide (InP) layer. The AlGaAs uses an ion implantation model for a design purpose which lowers the thermal power while the operation of the device. The parasitic capacitance has to be taken care of while designing a device using this material since the capacitance affects much in the AlGaAs based devices. The average velocity of the electrons has been observed to be increased by 14.63 % in the Au-gate (gate-1) and Pt-gate (gate-2) material-based Double-Gate (DG) MOSFET compared to the Silicon-based DG MOSFET. This paves the way for higher electron mobility, in turn, it can be used in highfrequency device manufacturing. The proposed material can be used in high-speed hybrid applications such as HEMTs and radiofrequency devices for long-haul communication.

Characterization and Ex Vivo Application of Indocyanine Green Chitosan Patches in Dura Mater Laser Bonding

Dura mater repair represents a final and crucial step in neurosurgery: an inadequate dural reconstruction determines dreadful consequences that significantly increase morbidity and mortality rates. Different dural substitutes have been used with suboptimal results. To overcome this issue, in previous studies, we proposed a laser-based approach to the bonding of porcine dura mater, evidencing the feasibility of the laser-assisted procedure. In this work, we present the optimization of this approach in ex vivo experiments performed on porcine dura mater. An 810-nm continuous-wave AlGaAs (Aluminium Gallium Arsenide) diode laser was used for welding Indocyanine Green-loaded patches (ICG patches) to the dura. The ICG-loaded patches were fabricated using chitosan, a resistant, pliable and stable in the physiological environment biopolymer; moreover, their absorption peak was very close to the laser emission wavelength. Histology, thermal imaging and leak pressure tests were used to evaluate the bonding effect. We demonstrated that the application of 3 watts (W), pulsed mode (Ton 30 ms, Toff 3.5 ms) laser light induces optimal welding of the ICG patch to the dura mater, ensuring an average fluid leakage pressure of 216 ± 105 mmHg, falling within the range of physiological parameters. This study demonstrated that the thermal effect is limited and spatially confined and that the laser bonding procedure can be used to close the dura mater. Our results showed the effectiveness of this approach and encourage further experiments in in vivo models.

FIELD AND THERMIONIC FIELD TRANSPORT IN ALUMINIUM GALLIUM ARSENIDE HETEROJUNCTION BARRIERS

A simplified model of electron transport by tunneling within a GaAs/AlGaAs/GaAs heterojunction is developed. The model is applied specifically to tunneling through a triangular barrier formed by the compositional grading of the AlGaAs region, but can in principle be extended to a range of barrier geometries encountered at heterojunction or metal/semiconductor interfaces. The experimental data for the current-voltage characteristics obtained for a range of temperatures from 77 K to 273 K are used to test the functional dependence obtained from calculations. Good agreement has been obtained between theory and experiment, thus confirming the usefulness of the simple model for device evaluation.