Three-dimensional (3D) architectures of graphene derivatives have attracted intensive attention due to their outstanding electric conductance and unique interconnected huge surface area. It is expected to transfer these excellent properties of 3D graphene into microsystems for further development in the microelectronic industry. However, limited applications are reported due to the absence of suitable fabrication approaches of 3D graphene that are compatible with existing silicon-based microfabrication techniques. In this paper, a novel 3D hierarchical graphene was prepared using a plasma-enhanced chemical vapor deposition to synthesize graphene nanoflakes on silicon nanowires (SiNWs) scaffolds that are generated from metal-assisted chemical etching (MACE). In addition to the first growth mechanism study of graphene on different substrates, the application of 3D graphene derivatives was further explored towards energy storage through an electrochemical evaluation. The 3D graphene electrode, combined with pseudocapacitive polyaniline coating, showed a large specific capacitance of 185 mF cm ⁻² , which outperforms its planar counterparts and is desirable for constructing micro-supercapacitors towards chip-scale power supplying. Above all, this microfabrication strategy of 3D graphene on high aspect ratio silicon nanostructures can also be extended as a platform toolkit towards the application of micro-batteries, solar cells and sensors in microsystems.

In this paper, a centimeter-scale monolayer molybdenum disulfide (MoS ₂ ) film deposition method has been developed through a simple low-pressure chemical vapor deposition (LPCVD) growth system. The growth pressure dependence on film quality is investigated in this LPCVD system. The layer nature, electrical characteristic of the as-grown MoS ₂ films indicate that high quality films have been achieved. In addition, a hydrofluoric acid treated SiO ₂ /Si substrate is used to improve the quality of the MoS ₂ films. Piezoresistive strain sensor based on the monolayer MoS ₂ film elements is fabricated by directly patterning metal contact pads on MoS ₂ films through a silicon stencil mask. A gauge factor of 104 ± 26 under compressive strain is obtained by using a four-point bending method, which may inspire new possibilities for two-dimensional (2D) material-based microsystems and electronics.

MEMS Laser beam scanning (LBS) has been identified as a key advancement for augmented reality (AR) displays due to its ability to create compact optical systems that generate bright, high-contrast images with minimal heat dissipation. This innovation can be attributed to the focus-free, efficient light-on-demand pixel projection mechanisms integral to LBS. The LBS, specifically in Lissajous-mode, outperforms the raster-mode in terms of larger scan angles and stability to external vibrations, by leveraging a MEMS mirror operating at bi-axial resonance. However, it tends to be hampered by small mirror aperture, low fill-factor, and inconsistent uniformity of image projection. In this research, a unique gimbal-less Lissajous MEMS scanner was proposed. It employs a bi-axial high frequency of 12,255 Hz and 7,182 Hz to achieve a resolution of 640 × 360 pixels and a video refresh rate of 57 Hz, all while maintaining a high image fill factor of 85.11%. The robust structure of the mirror is proven to sustain stable scanning under broad spectrum of external vibration disturbance up to 2,000 Hz. Furthermore, the large mirror diameter of 2 mm improves refined pixel projection and increased optical etendue for exit pupil. Mathematic model of Lissajous pixel-cells and image reconstruction simulation were established to validate the LBS's ability to generate a uniform and densely pixelated visual effect that fits for typical AR head-up display (AR-HUD). In a pioneering move, performance metric of figure-of-merit was defined to evaluate AR light-engines using varied picture-generation techniques, laying a foundation for guiding future AR system development.

The emergence of smart headlights with reconfigurable light distributions that provide optimal illumination, highlight road objects, and project symbols to communicate with traffic participants further enhances road safety. Integrating all these functions in a single headlight usually suffers from issues of bulky multi-functional add-on modules with high cost or the use of conventional spatial light modulators with low optical efficiency and complex thermal design requirements. This paper presents a novel laser headlight prototype based on biaxially resonant microelectromechanical systems (MEMS) mirror light modulator for mapping blue laser patterns on phosphor plate to create structured white illumination and tunable road projection. The proposed headlight prototype system enables reconfigurable light distribution by leveraging laser beam scanning with fewer back-end lens and simple thermal design requirements. Built with thin-film lead zirconate titanate oxide (PbZrTiO₃) actuators, the MEMS mirror achieved high-frequency biaxial resonance of 17.328 kHz, 4.81 kHz, and optical scan angle of 12.9°. The large mirror design of 2.0 mm facilitates more refined resolvable projection pixels, delivers more optical power, and provides moderate optical aperture to possibly serve as the common spatial light modulator of headlight and the light detection and ranging (LiDAR) towards all-in-one integration. The carefully designed bi-axial resonant frequency improves the device’s robustness by offsetting the lowest eigenmode away from the vehicle vibration. By establishing the laser headlight prototype systems of both 1D and 2D scanning modes, a mathematical model of laser modulation and MEMS electrical control principles of Lissajous scanning are proposed to tune the projection pattern density and shapes. It laid the foundation for developing a laser scanning control system with more complex project functions and prompting the application of MEMS for compact headlight system that addresses night driving visibility, eliminates glare effect, and renders interactive projection capabilities.