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Ultra-high mobility speciality is a critical figure of merit for ultrapure materials and high-speed optoelectronic devices. However, unintentional doping-inducing various scattering frequently deteriorates mobility capacity. Therefore, how to elucidate the origin of mobility deterioration is still an open and technically challenging issue. Here we report that unintentional-doping silicon ion would be propagated into the indium phosphide (InP)’s epitaxial layer via analysis of time-of-flight and dynamic secondary ion mass spectrometry. The unintentional silicon ion in the InP wafer surface is responsible for the subsequent InGaAs epitaxial layer's mobility attenuation. The first-principles calculations and Boltzmann transport theory prove that polar optical phonon scattering (Fröhlich scattering) in non-doping InGaAs is the dominant scattering mechanism at high temperatures over 100 K. In contrast, the low-temperature scattering process is dominated by ionized impurities scattering. The unintentional silicon ion improves the Fröhlich scattering-dominated critical temperature. Our findings provide insight into the mobility degeneration originating from unintentional pollution and underlying scattering mechanisms, which lay a solid foundation for developing high-grade, super-speed, and low-power photoelectronic devices.

Solar-blind photodetectors (SBPDs) are core essential components for many critical applications such as precision guidance, fire warning, and space communications. Ultra-wide bandgap semiconductor β-Ga₂O₃ is considered to be an ideal material for the fabrication of SBPDs. However, synthetizing β-Ga₂O₃ with high quality factor while simultaneously in situ modulation of electronic and optoelectronic properties to enhance performance has been challenging. Here, pulsed laser deposition (PLD) technology is used to synthesize high-quality β-Ga₂O₃ thin films on a sapphire substrate. The oxygen vacancy engineered β-Ga₂O₃ films can achieve in situ precise control of their surface morphology, optical parameters, and optoelectronic properties by simply adjusting the oxygen pressure. Meanwhile, the optimal thickness of the β-Ga₂O₃ film for the developing high-performance SBPD is ∼221 nm, determined by fitting and analyzing the optical parameters measured by the ellipsometry. Subsequently, the influence of oxygen pressure on the performance of β-Ga₂O₃ SBPD is thoroughly explored, considering the optimization of electrode size and deposition time. When the oxygen pressure is set to 15 Pa, the β-Ga₂O₃-based SBPD achieves highly competitive responsivity (R) and detectivity (D*) at 250 nm, with values of 1080 A·W⁻¹ and 1.4 × 10¹⁶ cm·W⁻¹·Hz^1/2, respectively. Additionally, the noise component of the β-Ga₂O₃ SBPD is further studied to calibrated the traditional device performance results. This work introduces a simple and straightforward approach to in situ tuning of the optoelectronic properties of β-Ga₂O₃, which is important for advancing β-Ga₂O₃ film growth technology and fabricating high-performance photodetectors.

Ferroic domains and relevant topological defects, such as domain walls and vortices, have gained significant attention as functional units for potential advancements in nanoelectronics. Pb(Zr_xTi_1-x)O₃ (PZT) is a tetragonal ferroelectric material at room-temperature, exhibiting remarkable piezoelectricity and intricate domain structures. In this work, we explore the ferroelectric properties, photoelectric reactions, and efficient manipulation pathways of the unconventional superstructures in epitaxial (101)-oriented PZT thin films. Employing piezoresponse force microscopy (PFM) and conductive atomic force microscopy (cAFM), we unveil the three-dimensional polarization configurations of the superdomain structures inherently featuring conductive charged domain walls. Our findings reveal an increase in photoactivity at the head-side charged domain walls, attributed to the band-bending mechanism. Additionally, we discover the enhanced photoelectrochemical (PEC) performance in the superdomain structures compared to the (101)-oriented PZT films with conventional c/a domains. Furthermore, time-dependent pulse voltages are utilized to dynamically assess local currents and realize direct conductivity modulation by manipulating distinct polarization states. The elucidation of the photoelectrical mechanism and delineation of diverse pathways for intermediate state control underscore the potential of ferroelectric superdomains in constructing functional photoelectronic nanodevices.

Resistive-switching (RS) memory devices, or memristors, necessitate active materials of which electronic resistance is tunable by an external electric field. Metal halide perovskites (MHP) are representative RS materials wherein the electronic resistance is modulated by migration of intrinsic native or extrinsic impurity mobile ions. Since the first demonstration of MHP-based RS memory nearly a decade ago, MHPs have proven their great potential for energy-efficient nonvolatile memory devices. Dynamic transport of the mobile ions further allows MHPs to exhibit multistate resistance tunability at multiple timescale, which can be harnessed for neuromorphic memristors. Herein, we provide a comprehensive review on progress in RS memory devices with MHPs and their applications for neuromorphic memristors. We discuss how the electronic resistance of the MHPs is modulated by dynamic mobile ions, and focus on the ionic-electronic correlation that involves doping phenomena in MHPs on account of previous theoretical predictions and experimental verifications. Finally, we provide our perspective on major hurdles of MHPs for real-world applications of emerging nonvolatile memory and neuromorphic memristor technology.

This study conducts a comprehensive first-principles analysis of the structural, mechanical, phonon dispersion, and electronic properties of XMg₂Hg, XMgHg₂, and X₂MgHg (X = Sc and Li) compounds. Using energy-volume curves, cohesive and formation energy, and phonon dispersion analyses, we confirm the stability of these compounds. Our calculations reveal that Li₂MgHg and ScMg₂Hg are more stable in the cubic structure with space group $F\overline{4}3m$ (216), whereas other compounds are stable in the $\text{Fm}\overline{3}m$ (225) structure. Phonon dispersion calculations indicate dynamical stability for all compounds except Li₂MgHg in the $\text{Fm}\overline{3}m$ structure and Sc₂MgHg and LiMg₂Hg in the cubic structure with space group $F\overline{4}3m$ (216). Mechanical stability is confirmed through the calculation of elastic constants, with Sc-based compounds showing higher bulk modulus, shear modulus, and Young's modulus compared to Li-based compounds. Electronic properties, analyzed through density of states and band structure calculations, confirm the metallic nature of these compounds, with significant contributions from Mg atoms at the Fermi energy. The study also identifies distinct electronic features such as flat electron bands and a Dirac point at the Gamma point for ScMgHg₂​. Pressure-dependent studies indicate these materials are normal metals without topological phase transitions.

This study explores the fabrication and charge transport behavior of MXene-polymer nanocomposite-based self-assembled floating films at the air-liquid interface. Utilizing ultrasonic dispersion of MXene nanosheets was integrated into a DPP-TTT polymer matrix, significantly enhancing the alignment and crystallization of the polymer chains. The films were fabricated using a unidirectional floating film transfer method (UFTM), which proved to be both simple and cost-effective. UV–visible and grazing incidence X-ray diffraction (GIXD) analyses confirmed increased π–π stacking and improved structural arrangement within the nanocomposites. Organic field-effect transistors (OFETs) fabricated from these films demonstrated that a 3% MXene inclusion resulted in the highest mobility, measuring 3.1 cm²V^-1s^-1 with an on-off ratio in the order of 10⁴, compared to 1.3 cm²V^-1s^-1 in pristine DPP-TTT films. However, further increases in MXene content reduced mobility, emphasizing the importance of precise compositional tuning.

Halide perovskites are gaining prominence as promising materials for future electronic applications, primarily due to their unique properties including long carrier diffusion lengths, tunable bandgap, facile synthesis, and cost efficiency. However, polycrystalline halide perovskite thin films, which have been widely studied to date, have significant drawbacks including uncontrollable grain boundaries and instability issues. Recently, low-dimensional halide perovskites (LD HPs) offer enhanced stability and adaptable morphologies, making them attractive candidates for next-generation electronics beyond optoelectronics. This review comprehensively explores recent advancements in LD HP-based electronics, covering structural characteristics, synthesis methods tailored to different dimensions, and diverse applications. Furthermore, the impressive performance demonstrated by LD HPs in electronic applications including resistive random-access memory, advanced transistors, and neuromorphic computing hardware is discussed. Finally, the review outlines the challenges and perspectives required to scale up LD HP-based advanced electronics for commercial production, offering valuable insights for researchers venturing into the realm of new materials for advanced electronics.

In recent years, metal halide perovskite materials have been successfully adopted in various optoelectronic applications, owing to their remarkable material properties. Notably, the piezo-phototronic effect (a coining effect of piezoelectric, semiconducting and photoexcitation properties) in metal halide perovskite can be expected to further enhance device performances. In this review, we provide a comprehensive overview of metal halide perovskite materials and their recent advancements through the utilization of the piezo-phototronic effect and the pyro-phototronic effect. Firstly, the molecular structure, growing methods, optical and piezoelectric properties of perovskite are discussed. Subsequently, this review delves into the fundamental principles and practical applications of the piezo-phototronic effect, emphasizing its significance in diverse fields such as. Thirdly, recent studies on the pyro-phototronic effect, spintronics, and light emission are surveyed. Last but not least, challenges that may hinder the development of the piezo-phototronic effect and pyro-phototronic effect in perovskites are summarized. This review emphasizes the advances in the application of the piezo-/pyro-phototronic effect in perovskite-based optoelectronic devices. It aims to provide a comprehensive understanding of the piezo-/pyro-phototronic effect as an effective tool to enhance device performances as well as to inspire potential design for high-performance perovskite-based optoelectronic devices in the future.