Abstract Over the past 70 years, the semiconductor industry has undergone transformative changes, largely driven by the miniaturization of devices and the integration of innovative structures and materials. Two-dimensional (2D) materials like transition metal dichalcogenides (TMDs) and graphene are pivotal in overcoming the limitations of silicon-based technologies, offering innovative approaches in transistor design and functionality, enabling atomic-thin channel transistors and monolithic 3D integration. We review the important progress in the application of 2D materials in future information technology, focusing in particular on microelectronics and optoelectronics. We comprehensively summarize the key advancements across material production, characterization metrology, electronic devices, optoelectronic devices, and heterogeneous integration on silicon. A strategic roadmap and key challenges for the transition of 2D materials from basic research to industrial development are outlined. To facilitate such a transition, key technologies and tools dedicated to 2D materials must be developed to meet industrial standards, and the employment of AI in material growth, characterizations, and circuit design will be essential. It is time for academia to actively engage with industry to drive the next 10 years of 2D material research.

Targeting the simultaneous wireless charging of multiple receiver (RX) coils, we developed a coupling coefficient (${k}$) sensorless wireless power transfer (WPT) system enabled by the proposed adaptive magnetic field distributor (AMFD) IC. By simply measuring the voltages and currents on the transmitter (TX) side free of knowing the${k}$between each pair of coils, the system can optimize the current in each TX coil to optimize the generated magnetic fields at each RX coil to maximize the system efficiency ($\eta _{\mathbf {SYS}}$). A current sensor calibration (CSC) technique was also proposed to guarantee the accurate on-chip current sensing in the AMFD IC. The AMFD IC was fabricated by a$0.18~\mu $m CMOS process with 1.8 V devices. Owing to the CSC technique, an accurate on-chip current sensing could be performed with a percentage error within ±4.5 %. A WPT system consisting of 2 TX coils driven by 2 AMFD ICs and 2 RX coils was implemented. Experimental results showed that, compared with the conventional WPT method,$\eta _{\mathbf {SYS}}$in the developed system was increased from 16 % to 65 % with a load power of 276 mW when the RX coils were perpendicular to the TX coils. When the RX coils were parallel to the TX coils, a high$\eta _{\mathbf {SYS}}$of 78 % was also obtained.

In this work, a 6.78 MHz three-coil wireless power transfer (WPT) system was presented, which consists of a transmitter (TX) coil, a reconfigurable relay coil (RRC), and a receiver (RX) coil. We analytically derived the critical coupling boundary and impedance matching (IM) condition in the strong-coupling regime for the first time. Under the variation of either coupling coefficient$\boldsymbol {k}$or load resistance$\boldsymbol {R}_{\text {L}}$, we proposed to achieve the IM condition on both TX and RX sides by adjusting the RRC’s inductance through electronically selecting its constituting loops. This eliminates the coupling tuning related with the mechanical position change. To obtain the optimum loop inductance in the RRC, we simply measured the voltage and current on the TX side without requiring information of$\boldsymbol {k}$or$\boldsymbol { R}_{\text {L}}$. This eliminates the RX-to-TX communication link. We implemented a prototype WPT system by including a class-D power amplifier (PA) and a rectifier, and the effectiveness of IM was verified under variations of$\boldsymbol {k}$and$\boldsymbol {R}_{\text {L}}$. Compared with the system without IM, the transmission ratio$\boldsymbol { S}_{{21}}$and load power$\boldsymbol {P}_{\text {Load}}$were respectively increased from 66.5 % to 77.9 % and 4.2 W to 10.2 W at$\boldsymbol {k} = 0.15$and$\boldsymbol {R}_{\text {L}} = 20~\Omega $. Furthermore, the performance improvement of our system for the wireless charging of multiple RX coils was demonstrated.

Load shift keying (LSK) has been widely used in a wireless power and data transfer (WPDT) system, owing to its low cost and power consumption. It was discovered that the demodulated data can flip when the coupling coefficient ($k$) between the transmitter (TX) and receiver (RX) coils becomes less than a critical value ($k_{\mathrm {DF}}$) in a system with four basic compensation topologies (series–series, series–parallel, parallel–series, and parallel–parallel). This problem is called coupling-dependent data flipping (CDDF). Even more seriously, the transferred data cannot be recovered when$k$equals$k_{\mathrm {DF}}$. On the basis of a comprehensive circuit analysis of CDDF, a universal method applicable to all four compensation topologies was proposed. By monitoring the current through the TX coil rather than its voltage for data demodulation, CDDF can be avoided. Furthermore, a WPDT system was implemented in which the voltage information of the load resistance ($R_{\mathrm {Load}}$) was transferred to the TX side to control the source voltage for load power ($P_{\mathrm {Load}}$) regulation. Using the conventional method, CDDF along with its corresponding$k_{\mathrm {DF}}$(0.35) was verified. On the other hand, using the proposed method, the data was successfully transferred even when$k$is less than or equal to$k_{\mathrm {DF}}$. By a correct data transfer,$P_{\mathrm {Load}}$has been successfully regulated at around 1.1 W with a high system efficiency of up to 60% under the variation in$k$from 0.09 to 0.45.

We present the first demonstration of a battery-free untethered wirelessly powered sub-gram jumping robot on an insect-scale. In order to operate the insect-sized robot autonomously, the limitation in battery use emphasizes the need for a wireless power transmission system as an onboard power solution. We designed a wireless power transmission system based on inductive coupling to power the Shape Memory Alloy (SMA), which serves as an elastic energy storage element and actuator for the jumping robot. The assembled mechanical structures, onboard power and electronics yield a 2 mm (high) × 24 mm (long) × 12 mm (wide) robot with ~a weight of 216 mg. The experiments show that our jumping robot wirelessly lift-off up to 5.75 times its body length and repeats the jump around 7 times per minute. To date, out of the several untethered sub-gram insect-scale jumping robots with onboard power, this is the first wirelessly powered robot with the highest jumping performance. The novelty in this work, which addresses the engineering challenges in insect-scale jumping robots, is an untethered wirelessly powered design that achieves dynamic jumping maneuvers, and has self-righting ability.

Load modulation is a common method to transfer data from the receiver (RX) side to the transmitter (TX) side in a magnetic resonance coupling wireless power transfer system. However, coupling-dependent data flipping (CDDF), that the data can be flipped depending on the coupling between TX and RX coils, is found for the first time using the conventional voltage monitoring across the TX coil. An analytic formula of the critical coupling coefficient (kC) of the coils that determines CDDF is derived. To avoid CDDF, a TX input voltage monitoring method is proposed. Both the CDDF in the conventional method and the correct data transfer without CDDF in the proposed method are demonstrated in the measurement.