CMOS technology is one of the most frequently used technologies in the semiconductor industry as it can be successfully integrated with ICs. Every two years the number of MOS transistors doubles because the size of the MOSFET is reduced. Reducing the size of the MOSFET reduces the size of the channel length which causes short channel effects and it increases the leakage current. To reduce the short channel effects new designs and technologies are implemented. Double gate MOSFET design has shown improvement in performance as amplifiers over a single MOSFET. Silicon-based MOSFET design can be used in a harsh environment. It has been used in various applications such as in detecting biomolecules. The increase in number of gates increases the current drive capability of transistors. GAA MOSFET is an example of a quadruple gate around the four sides of channel that increases gate control over the channel region. It also increases effective channel width that improves drain current and reduces leakage current keeping short channel effects under limit. Junctionless MOSFET operates faster and uses less power with increase in ON-state current leading to a good value of I_ON/I_OFF ratio. In this paper, several gate and channel engineered MOSFET structures are analyzed and compared for sub 45 nm technology node. A comparison among different MOSFET structures has been made for subthreshold performance parameters in terms of I_OFF, subthreshold slope and DIBL values. The analog/RF performance is analyzed for transconductance, effective transistor capacitances, stability factor and critical frequency. The paper also covers different applications of advance MOSFET structures in analog/digital or IoT/ biomedical applications.

2D material of graphene has inspired huge interest in fabricating of solid state gas sensors. In this work, epitaxial graphene, quasi-free-standing graphene, and CVD epitaxial graphene samples on SiC substrates are used to fabricate gas sensors. Defects are introduced into graphene using SF₆ plasma treatment to improve the performance of the gas sensors. The epitaxial graphene shows high sensitivity to NO₂ with response of 105.1% to 4 ppm NO₂ and detection limit of 1 ppb. The higher sensitivity of epitaxial graphene compared to quasi-free-standing graphene, and CVD epitaxial graphene was found to be related to the different doping types of the samples.

Hybrid white micro-pillar structure light emitting diodes (LEDs) have been manufacture utilizing blue micro-LEDs arrays integrated with 580 nm CIS ((CuInS₂-ZnS)/ZnS) core/shell quantum dots. The fabricated hybrid white micro-LEDs have good electrical properties, which are manifested in relatively low turn-on voltage and reverse leakage current. High-quality hybrid white light emission has been demonstrated by the hybrid white micro-LEDs after a systemic optimization, in which the corresponding color coordinates are calculated to be (0.3303, 0.3501) and the calculated color temperature is 5596 K. This result indicates an effective way to achieve high-performance white LEDs and shows great promise in a large range of applications in the future including micro-displays, bioinstrumentation and visible light communication.

Soft robots complement the existing efforts of miniaturizing conventional, rigid robots, and have the potential to revolutionize areas such as military equipment and biomedical devices. This type of system can accomplish tasks in complex and time-varying environments through geometric reconfiguration induced by diverse external stimuli, such as heat, solvent, light, electric field, magnetic field, and mechanical field. Approaches to achieve reconfigurable mesostructures are essential to the design and fabrication of soft robots. Existing studies mainly focus on four key aspects: reconfiguration mechanisms, fabrication schemes, deformation control principles, and practical applications. This review presents a detailed survey of methodologies for morphable mesostructures triggered by a wide range of stimuli, with a number of impressive examples, demonstrating high degrees of deformation complexities and varied multi-functionalities. The latest progress based on the development of new materials and unique design concepts is highlighted. An outlook on the remaining challenges and open opportunities is provided.

Aluminum nitride (AlN) has attracted a great amount of interest due to the fact that these group III–V semiconductors present direct band gap behavior and are compatible with current micro-electro-mechanical systems. In this work, three dimensional (3D) AlN architectures including tubes and helices were constructed by rolling up AlN nanomembranes grown on a silicon-on-insulator wafer via magnetron sputtering. The properties of the AlN membrane were characterized through transmission electron microscopy and X-ray diffraction. The thickness of AlN nanomembranes could be tuned via the RIE thinning method, and thus micro-tubes with different diameters were fabricated. The intrinsic strain in AlN membranes was investigated via micro-Raman spectroscopy, which agrees well with theory prediction. Whispering gallery mode was observed in AlN tubular optical microcavity in photoluminescence spectrum. A postprocess involving atomic layer deposition and R6G immersion were employed on as-fabricated AlN tubes to promote the Q-factor. The AlN tubular micro-resonators could offer a novel design route for Si-based integrated light sources. In addition, the rolled-up technology paves a new way for AlN 3D structure fabrication, which is promising for AlN application in MEMS and photonics fields.

Current electronics are driven by advanced microfabrication for fast and efficient information processing. In spite of high performance, these wafer-based devices are rigid, non-degradable, and unable to autonomous repair. Skin-inspired electronics have emerged as a new class of devices and systems for next-generation flexible and wearable electronics. The technology gains inspiration from the structures, properties, and sensing mechanisms of the skin, which may find a broad range of applications in cutting-edge fields such as healthcare monitoring, human-machine interface, and soft robotics/prostheses. Practical demands have fueled the development of electronic materials with skin-like properties in terms of stretchability, self-healing capability, and biodegradability. These materials provide the basis for functional sensors with innovative and biomimetic designs. Further system-level integrations and optimizations enable new forms of electronics for real-world applications. This review summarizes recent advancements in this active area and speculates on future directions.

A very highly efficient InGaAlAs/AlGaAs quantum-well structure was designed for 808 nm emission, and laser diode chips 390-μm-wide aperture and 2-mm-long cavity length were fabricated. Special pretreatment and passivation for the chip facets were performed to achieve improved reliability performance. The laser chips were p-side-down mounted on the AlN sub-mount, and then tested at continuous wave (CW) operation with the heat-sink temperature setting to 25 °C using a thermoelectric cooler (TEC). As high as 60.5% of the wall-plug efficiency (WPE) was achieved at the injection current of 11 A. The maximum output power of 30.1 W was obtained at 29.5 A when the TEC temperature was set to 12 °C. Accelerated life-time test showed that the laser diodes had lifetimes of over 62 111 h operating at rated power of 10 W.

Flexible light-emitting diodes (LEDs) are highly desired for wearable devices, flexible displays, robotics, biomedicine, etc. Traditionally, the transfer process of an ultrathin wafer of about 10–30 μm to a flexible substrate is utilized. However, the yield is low, and it is not applicable to thick GaN LED chips with a 100 μm sapphire substrate. In this paper, transferable LED chips utilized the mature LED manufacture technique are developed, which possesses the advantage of high yield. The flexible LED array demonstrates good electrical and optical performance.

Laser induced periodic surface structures (LIPSS) represent a kind of top down approach to produce highly reproducible nano/microstructures without going for any sophisticated process of lithography. This method is much simpler and cost effective. In this work, LIPSS on Si surfaces were generated using femtosecond laser pulses of 800 nm wavelength. Photocatalytic substrates were prepared by depositing TiO₂ thin films on top of the structured and unstructured Si wafer. The coatings were produced by sputtering from a Ti target in two different types of oxygen atmospheres. In first case, the oxygen pressure within the sputtering chamber was chosen to be high (3 × 10^–2 mbar) whereas it was one order of magnitude lower in second case (2.1 × 10^–3 mbar). In photocatalytic dye decomposition study of Methylene blue dye it was found that in the presence of LIPSS the activity can be enhanced by 2.1 and 3.3 times with high pressure and low pressure grown TiO₂ thin films, respectively. The increase in photocatalytic activity is attributed to the enlargement of effective surface area. In comparative study, the dye decomposition rates of TiO₂ thin films grown on LIPSS are found to be much higher than the value for standard reference thin film material Pilkington Activ^TM.

The 4-level pulse amplitude modulation (PAM4) based on an 23 GHz ultrabroadband directly modulated laser (DML) was proposed. We have experimentally demonstrated that based on intensity modulation and direct detection (IMDD) 56 Gbps per wavelength PAM4 signals transferred over 35 km standard single mode fiber (SSMF) without any optical amplification and we have achieved the bit error rate (BER) of the PAM4 transmission was under 2.9 × 10^–4 by using feed forward equalization (FFE).

The influence of self-heating on the millimeter-wave (mm-wave) and terahertz (THz) performance of double-drift region (DDR) impact avalanche transit time (IMPATT) sources based on silicon (Si) has been investigated in this paper. The dependences of static and large-signal parameters on junction temperature are estimated using a non-sinusoidal voltage excited (NSVE) large-signal simulation technique developed by the authors, which is based on the quantum-corrected drift-diffusion (QCDD) model. Linear variations of static parameters and non-linear variations of large-signal parameters with temperature have been observed. Analytical expressions representing the temperature dependences of static and large-signal parameters of the diodes are developed using linear and 2nd degree polynomial curve fitting techniques, which will be highly useful for optimizing the thermal design of the oscillators. Finally, the simulated results are found to be in close agreement with the experimentally measured data.

We use traveling wave coupling theory to investigate the time domain characteristics of tapered semiconductor lasers with DBR gratings. We analyze the influence of the length of second order gratings on the power and spectrum of output light, and optimizing the length of gratings, in order to reduce the mode competition effect in the device, and obtain the high power output light wave with good longitudinal mode characteristics.