GaN diodes for high energy (64.8 MeV) proton detection were fabricated and investigated. A comparison of the performance of GaN diodes with different structures is presented, with a focus on sapphire and on GaN substrates, Schottky and pin diodes, and different active layer thicknesses. Pin diodes fabricated on a sapphire substrate are the best choice for a GaN proton detector working at 0 V bias. They are sensitive (minimum detectable proton beam <1 pA/cm²), linear as a function of proton current and fast (<1 s). High proton current sensitivity and high spatial resolution of GaN diodes can be exploited in the future for proton imaging of patients in proton therapy.

Traditional p-type colloidal quantum dot (CQD) hole transport layers (HTLs) used in CQD solar cells (CQDSCs) are commonly based on organic ligands exchange and the layer-by-layer (LbL) technique. Nonetheless, the ligand detachment and complex fabrication process introduce surface defects, compromising device stability and efficiency. In this work, we propose a solution-phase ligand exchange (SPLE) method utilizing inorganic ligands to develop stable p-type lead sulfide (PbS) CQD inks for the first time. Various amounts of tin (II) iodide (SnI₂) were mixed with lead halide (PbX₂; X = I, Br) in the ligand solution. By precisely controlling the SnI₂ concentration, we regulate the transition of PbS QDs from n-type to p-type. PbS CQDSCs were fabricated using two different HTL approaches: one with 1,2-ethanedithiol (EDT)-passivated QDs via the LbL method (control) and another with inorganic ligand-passivated QD ink (target). The target devices achieved a higher power conversion efficiency (PCE) of 10.93%, compared to 9.83% for the control devices. This improvement is attributed to reduced interfacial defects and enhanced carrier mobility. The proposed technique offers an efficient pathway for producing stable p-type PbS CQD inks using inorganic ligands, paving the way for high-performance and flexible CQD-based optoelectronic devices.

The heterogeneous integration of III–V devices with Si-CMOS on a common Si platform has shown great promise in the new generations of electrical and optical systems for novel applications, such as HEMT or LED with integrated control circuitry. For heterogeneous integration, direct wafer bonding (DWB) techniques can overcome the materials and thermal mismatch issues by directly bonding dissimilar materials systems and device structures together. In addition, DWB can perform at wafer-level, which eases the requirements for integration alignment and increases the scalability for volume production. In this paper, a brief review of the different bonding technologies is discussed. After that, three main DWB techniques of single-, double- and multi-bonding are presented with the demonstrations of various heterogeneous integration applications. Meanwhile, the integration challenges, such as micro-defects, surface roughness and bonding yield are discussed in detail.

Perovskite materials have emerged as promising candidates for various optoelectronic applications owing to their remarkable optoelectronic properties and easy solution processing. Metal halide perovskites, as direct-bandgap semiconductors, show an excellent class of optical gain media, which makes them applicable to the development of low-threshold or even thresholdless lasers. This mini review explores recent advances in perovskite-based laser technology, which have led to chiral single-mode microlasers, low-threshold, external-cavity-free lasing devices at room temperature, and other innovative device architectures. Including self-assembled CsPbBr₃ microwires that enable edge lasing. Realized continuous-wave (CW) pumped lasing by perovskite material pushes the research of electrically driven perovskite lasers. The capacity to regulate charge transport in halide perovskites further enhances their applicability in optoelectronic systems. The ongoing integration of perovskite materials with advanced photonic structures holds excellent potential for future innovations in laser technology and photovoltaics. We also highlight the transformative potential of perovskite materials in advancing the next generation of efficient and integrated optoelectronic devices.

Infrared and terahertz waves constitute pivotal bands within the electromagnetic spectrum, distinguished by their robust penetration capabilities and non-ionizing nature. These wavebands offer the potential for achieving high-resolution and non-destructive detection methodologies, thereby possessing considerable research significance across diverse domains including communication technologies, biomedical applications, and security screening systems. Two-dimensional materials, owing to their distinctive optoelectronic attributes, have found widespread application in photodetection endeavors. Nonetheless, their efficacy diminishes when tasked with detecting lower photon energies. Furthermore, as the landscape of device integration evolves, two-dimensional materials struggle to align with the stringent demands for device superior performance. Topological materials, with their topologically protected electronic states and non-trivial topological invariants, exhibit quantum anomalous Hall effects and ultra-high carrier mobility, providing a new approach for seeking photosensitive materials for infrared and terahertz photodetectors. This article introduces various types of topological materials and their properties, followed by an explanation of the detection mechanism and performance parameters of photodetectors. Finally, it summarizes the current research status of near-infrared to far-infrared photodetectors and terahertz photodetectors based on topological materials, discussing the challenges faced and future prospects in their development.

Digital to analog converters (DAC) play an important role as a bridge connecting the analog world and the digital world. With the rapid development of wireless communication, wideband digital radar, and other emerging technologies, better performing high-speed high-resolution DACs are required. In those applications, signal bandwidth and high-frequency linearity often limited by data converters are the bottleneck of the system. This article reviews the state-of-the-art technologies of high-speed and high-resolution DACs reported in recent years. Comparisons are made between different architectures, circuit implementations and calibration techniques along with the figure of merit (FoM) results.

This work presents a high-gain broadband inverter-based cascode transimpedance amplifier fabricated in a 65-nm CMOS process. Multiple bandwidth enhancement techniques, including input bonding wire, input series on-chip inductive peaking and negative capacitance compensation, are adopted to overcome the large off-chip photodiode capacitive loading and the miller capacitance of the input device, achieving an overall bandwidth enhancement ratio of 8.5. The electrical measurement shows TIA achieves 58 dBΩ up to 12.7 GHz with a 180-fF off-chip photodetector. The optical measurement demonstrates a clear open eye of 20 Gb/s. The TIA dissipates 4 mW from a 1.2-V supply voltage.

CMOS analog and mixed-signal phase-locked loops (PLL) are widely used in varies of the system-on-chips (SoC) as the clock generator or frequency synthesizer. This paper presents an overview of the AMS-PLL, including: 1) a brief introduction of the basics of the charge-pump based PLL, which is the most widely used AMS-PLL architecture due to its simplicity and robustness; 2) a summary of the design issues of the basic CPPLL architecture; 3) a systematic introduction of the techniques for the performance enhancement of the CPPLL; 4) a brief overview of ultra-low-jitter AMS-PLL architectures which can achieve lower jitter (< 100 fs) with lower power consumption compared with the CPPLL, including the injection-locked PLL (ILPLL), sub-sampling (SSPLL) and sampling PLL (SPLL); 5) a discussion about the consideration of the AMS-PLL architecture selection, which could help designers meet their performance requirements.

Artificial intelligence (AI) processes data-centric applications with minimal effort. However, it poses new challenges to system design in terms of computational speed and energy efficiency. The traditional von Neumann architecture cannot meet the requirements of heavily data-centric applications due to the separation of computation and storage. The emergence of computing in-memory (CIM) is significant in circumventing the von Neumann bottleneck. A commercialized memory architecture, static random-access memory (SRAM), is fast and robust, consumes less power, and is compatible with state-of-the-art technology. This study investigates the research progress of SRAM-based CIM technology in three levels: circuit, function, and application. It also outlines the problems, challenges, and prospects of SRAM-based CIM macros.