Advanced Materials Research Vol. 1187

Abstract: To fabricate low threshold semiconductor lasers on silicon, strained quantum well structure is introduced to the well layer. The crystalline, optical, and laser characteristics of GaInAsP separate confinement heterostructure with multiple quantum wells (SCH-MQW) are investigated under various percentages of strain applied to the active layer. It is found that the strain-based III-V heterostructures possessed good crystalline and optical properties to study the current-light characteristics of the lasers. One of the successful achievements is that we do the laser growth only after fabricating InP thin film bonded to silicon substrate using hydrophilic bonding mechanism. GaInAsP SCH-MQW laser structures were fabricated on the directly bonded InP/Si substrate using metal-organic vapor phase epitaxy (MOVPE). Through our integration process and the intentional introduction of strain into the active layer, a significant reduction in threshold current was successfully achieved on the InP/Si substrate. Furthermore, a comparative analysis of the strain distribution within the quantum well structures between the InP and InP/Si substrates was conducted to better understand its impact on device performance.

Abstract: MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) technology has evolved rapidly in response to the demand for increased performance, lower power consumption, and ongoing device downsizing. This study provides a comparative review of various materials used in MOSFETs from 2021 to 2025, focusing on developments in channel ^materials as well as their features, advantages, and problems. While silicon (Si) and silicon-germanium (SiGe) continue to dominate mainstream technology, new materials such as indium gallium arsenide (InGaAs) and gallium nitride (GaN) have gained popularity. They are used for high-speed, low-power, and power electronics applications due to their superior electron mobility and high breakdown voltages. Two-dimensional (2D) materials like molybdenum disulfide (MoS₂) and black phosphorus (BP) show promise for ultra-thin, flexible, and energy-efficient devices. However, integrating them into large-scale manufacturing remains a challenge. Silicon is included into transistors, integrated circuits, and solar cells. SiGe excels in high-speed wireless transmission. GaN powers devices with high frequency and voltage, such as LEDs. SiC improves EV and renewable energy systems. InGaAs is essential for near-infrared photodetectors. Diamonds improve electronic cooling. MoS₂ supports field-effect transistors and photodetectors. This article also looks at continuing research into germanium (Ge) and other new materials, which have great mobility but suffer from leakage currents and fabrication complexity. The comparison of these materials provides insight into the future of MOSFET technology, helping researchers and industry professionals to next-generation semiconductor solutions.

Abstract: Intensive scaling of integrated circuits is one of the crucial factor for achieving high performance. However, this is pushing planar MOSFET to its physical limitations. FinFET has recently emergedas a promising alternative to planar MOSFETs, offering improved efficiency. This study presents acomparative analysis of FinFET and planar MOSFET technologies, focusing on their performance,structural advantages, and challenges in advanced technology nodes. The study highlights thesuperior short channel effect (SCE) control, reduced leakage current, reduced subthreshold slope,drain-induced barrier lowering (DIBL), and improved I-V and C-V characteristics of FinFETscompared to planar MOSFETs are been discussed. Tools like LTspice and Scilab are used forsimulation, as LTspice allows the simulation of MOSFET and FinFET behavior using detailedmodels, and Scilab provides a powerful environment for performing mathematical operations,plotting graphs, and analyzing simulation results obtained from LTspice. The extracted electricalparameters show FinFETs are more attractive for digital and low-frequency RF applications and areexpected to dominated planar MOSFETs in future generations. This comparative study providesvaluable insights into the growing dominance of FinFETs in high-performance circuits.

Abstract: Defect-induced magnetism (DIM) in otherwise nonmagnetic wide-band oxides had recently been explored in order to prepare oxide dilute magnetic semiconductor (O-DMSs) as the next-generation spintronic materials. In this context, effect of morphology-dependent surface-disorder and cationic-site defects in tailoring ferromagnetic behaviour and Raman vibrational modes were investigated systematically in series of indium (In)-substituted SnO₂ thin films fabricated by pulsed laser deposition (PLD) in oxygen-deficient Argon (Ar) atmosphere. Surface morphology of the SnO₂:In films had been changed as nanospheres (NSs), nanoflowers (NFs), nanoflakes (NFLs) and nanowires (NWs) with varying Ar pressure of 1, 10, 100 and 1000 Pa respectively. With increase of deposition pressure, crystallite size and thickness of the film decreased whereas surface disorder had enhanced considerably. Spectroscopic evidence revealed that both Sn vacancy (V_Sn), oxygen vacancy (V_O) defects were stabilized with enhanced surface disorder with the films. ESR spectroscopy indicated the presence of two major paramagnetic defect centres comprising Lande g-factor ~ 2.003, assigned to singly ionized V_O⁺ defect whereas other ‘g’ value about 1.89 were due to V_Sn defects or its complex with Vo defects. Being enriched with substantial paramagnetic defects, In-doped SnO₂ films exhibited enhanced high-T_C ferromagnetism. NWs of In:SnO₂ exhibited superior ferromagnetic signal with magnetic moment ~ 11.1 emu/cm³ and Curie temperature ~ 570 K. We attribute RKKY type magnetic interaction between magnetic of isolated V_Sn or associated defects complex like (V_Sn -Vo) mediated through the holes introduced due to In_Sn defects as the origin of FM in In:SnO₂ thin films. Therefore, the study depicts the promotion of cation vacancy defects by monitoring growth atmospheric conditions can be an effective way to achieve the oxide-based dilute magnetic semiconductors (O-DMSs) for spintronics applications.

Abstract: Ni_1-2xMg_xCu_xO and Ni_1-2xMg_xRu_xO nanoparticles (x = 0.005, 0.01, 0.02, 0.04, 0.08) were synthesized by the chemical co-precipitation method using salt chloride precursor and EDTA as a capping agent.The present work compares the impact of (Mg, Cu) and (Mg, Ru) co-dopants on the dielectric properties of NiO within a frequency range 0.1 -8 MHz and various dopant concentrations x = 0, 0.005, 0.01, 0.02, 0.04, 0.08. The dielectric properties and phase formation were investigated via an impedance analyser and XRD, respectively. X-ray diffraction patterns confirm the successful synthesis and crystallization of all Ni_1-2xMg_xCu_xO and Ni_1-2xMg_xRu_xO nanoparticles in the fcc structure except for Ni_0.92Mg_0.04Ru_0.04O and Ni_0.84Mg_0.08Ru_0.08O nanoparticles confirming a secondary RuO₂ pahse. Observed and calculated data from the impedance analyzer showed higher dielectric constants, ac conductivity, energy loss, and refractive index values for Ni_1-2xMg_xCu_xO than for Ni_1-2xMg_xRu_xO nanoparticles. However, the impedance values of (Mg, Ru) dual-doped NiO nanoparticles were higher compared with (Mg, Cu) dual-doped NiO nanoparticles. Both samples showed a decrease in dielectric constants, impedance, loss tangent, and refractive index as frequency increased (0.1-7.5MHz), with a vice versa behavior as dopant concentration rose, except for the impedance. Hence, Ni_1-2xMg_xCu_xO and Ni_1-2xMg_xRu_xO nanoparticles are good candidates for electrical and optical applications.

Abstract: Nano silica was synthesized using the Stober process with ammonia, ethanol, and tetraethyl orthosilicate (TEOS) solution. Equiatomic titanium-nickel pre-alloyed particles were reinforced with silica nanoparticles of constant volume percent with sizes varying as proceeding 50, 100, 250, and 500 nm. The weighed compositions were mixed in a planetary ball mill, followed by compaction via uniaxial compression of 50 MPa. The resultant green pellets were sintered in an argon atmosphere at 1223K for a period of 4 hrs. Following that, by using EDM, the composite pellets were sectioned, soldered, and cold-mounted. Microstructure was analyzed by optical microscopy, mechanical properties by micro-Vickers hardness testing, and electrochemical analysis by Tafel curves, whereas the effect of particle size at constant volume on the densification was determined via Archimedes' Principle. The reinforcement showed increasing hardness up to 120HV and an increase in phase distribution, in addition to the effect complemented by the transformation of silica, whereas the electrochemical evaluation was affected by both reinforcement and phase distribution. Electrochemical corrosion resistance was measured at 6.88mpy in pure TiNi and 10.93mpy in TiNi nano-silica composite.

Abstract: In this study, a bio-based slow-release nitrogen (N) fertilizer was developed using a novel composite material composed of natural rubber (NR) and lignin. To enhance its performance, the composite was further modified with epoxidized natural rubber (ENR), cassava starch (CS), and carboxymethyl cellulose (CMC). The chemical and mechanical properties of the resulting composites were thoroughly characterized using FT-IR spectroscopy and tensile strength measurements. FT-IR analysis revealed strong chemical interactions, particularly-COO stretching from CMC and-OH stretching from epoxide ring-opening and lignin, in the Lignin/NR/ENR/CMC composite. Among all formulations, the Lignin/NR/ENR/CMC film exhibited the highest tensile strength, indicating superior mechanical performance. The slow-release behavior of the composites was evaluated by monitoring cumulative nitrogen release in water. The Lignin/NR/ENR/CMC/Urea formulation demonstrated the most prolonged and controlled release profile, attributed to strong chemical interactions between CMC and the lignin matrix. SEM analysis further confirmed that CMC formed a uniform coating and potentially encapsulated lignin particles. This bio-based composite not only improves mechanical strength and chemical stability but also significantly enhances slow-release performance, making it a promising and sustainable alternative for agricultural fertilizer applications.

Abstract: The housing sector accounts for a high percentage of total energy consumption in Iraq, with most energy usage on air-conditioning systems in summer to provide comfort to residents. This study simulates energy consumption for a typical 200 m², two-story, single-family building in Al Amarah city, Iraq, to compare heating, cooling, and total energy use across three different building configurations. Locally manufactured hollow concrete blocks made with 40 × 20 × 20 cm3 dimensions were adopted to improve their thermal performance by filling the cavities with Polystyrene insulation. The research examined three residential building configurations: (i) a base case built with traditional fired-clay brick, (ii) hollow concrete block walls free of insulation, and (iii) hollow concrete block walls incorporating thermal insulation. Energy simulations using eQUEST software were conducted, utilising the thermal response factor method as the primary tool to analyse the impact of external environmental conditions on cooling and heating loads. The results demonstrated significant annual energy savings for the building with hollow concrete blocks with and without insulation. However, insulated hollow concrete blocks showed reduced annual energy consumption compared to the common brick building system. Specifically, the insulated and uninsulated blocks attained energy savings by 29.4% and 16.08%, respectively, for north-facing orientation.

Abstract: In this study, a comparative thermal performance analysis was conducted on three roof configurations under the hot climate of Iraq/Basra to evaluate their potential contribution to Nearly Zero Energy Building (nZEB) objectives. The first two models incorporated Phase Change Materials (PCM) with different melting points (24°C and 29°C) arranged in varying sequences, while the third model represented a traditional roof with EPS insulation and concrete. Annual simulations using Design Builder program assessed the impact of PCM layer arrangements on indoor thermal regulation and cooling energy demand reduction. Results demonstrated that the PCM-based roofs significantly reduced indoor temperature fluctuations compared to the traditional roof, directly translating to substantial reductions in cooling energy requirements a critical factor for nZEB feasibility in hot regions. The configuration with PCM29 on top followed by PCM24 proved most effective, consistently maintaining indoor temperatures within a narrower and more comfortable range with daily averages 32.7°C, thereby minimizing the need for active cooling. In stark contrast, the traditional roof exhibited higher variability with peaks exceeding 42°C, indicating significantly greater cooling loads. These findings highlight that strategic optimization of PCM layer arrangement in roofs is a highly effective passive cooling strategy. This approach not only enhances occupant comfort but also dramatically reduces building cooling energy consumption, representing a vital step towards achieving nearly zero energy building performance in energy-intensive arid climates.