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This study proposed a novel double-layer junction termination structure for vertical diamond-based PN junction diodes (PND). The effects of the geometry and doping concentration of the junction termination structure on the PNDs' electrical properties are investigated using Silvaco TCAD software (Version 5.0.10.R). It demonstrates that the electric performances of PND with a single n-type diamond layer are sensitive to the doping concentration and electrode location of the n-type diamond. To further suppress the electric field crowding and obtain a better balance between breakdown voltage and on-resistance, a double-layer junction termination structure is introduced and evaluated, yielding significantly improved electronic performances. Those results provide some useful thoughts for the design of vertical diamond PND devices. [ABSTRACT FROM AUTHOR]

The adaptability of living organisms to dynamically adjust their biological behavior in response to fluctuating surroundings is a prerequisite for their evolutionary success. However, artificially‐synthesized materials, especially semiconductors, have not been able to replicate such adaptability due to their inherent physical rigidity and lack of intrinsic structural responsiveness to external stimuli. Herein, an adaptive structural evolution in group‐III‐nitride semiconductors is demonstrated by constructing an AlGaN‐nanowire/Ni(OH)2 symbiotic‐system, resulting in self‐improved optoelectronic characteristics. The mutualistic interplay between AlGaN and Ni(OH)2 nanostructure leads to the adaptive evolution of crystalline‐facets of AlGaN‐nanowires, along with self‐optimization of Ni(OH)2 nanocrystals upon photon‐irradiation during its operation. Specifically, the nanowire‐surfaces dynamically evolve during Ni(OH)2 photo‐deposition, removing the (0001¯$\bar{1}$) plane while exposing the (101¯1¯$\bar{1}\bar{1}$), which facilitates carrier transport at AlGaN/Ni(OH)2 interface. Moreover, light‐induced electrons generated from AlGaN‐nanowires then partially reduce Ni2+ ions in the Ni(OH)2 nanostructure into Ni0 nanometals, which further boosts the proton reduction thermodynamics, generating an unusual self‐improving photocurrent from −59.6 to −101.6 µA cm−2. Such a "symbiotic system," which is barely observed in conventional semiconductors, provides a promising avenue toward realizing smart adaptive semiconductors that are capable of dynamic structural evolution to fully unleash their potential for emerging optoelectronic and artificial‐photocatalysis applications. [ABSTRACT FROM AUTHOR]

The novel design of carbon materials with stable nanoarchitecture and optimized electrical properties featuring simultaneous intercalation of lithium ions (Li+) and sodium ions (Na+) is of great significance for the superb lithium–sodium storage capacities. Biomass‐derived carbon materials with affluent porosity have been widely studied as anodes for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). However, it remains unexplored to further enhance the stability and utilization of the porous carbon skeleton during cycles. Here, a lotus stems derived porous carbon (LPC) with graphene quantum dots (GQDs) and intrinsic carbon nanowires framework (CNF) is successfully fabricated by a self‐template method. The LPC anodes show remarkable Li+ and Na+ storage performance with ultrahigh capacity (738 mA h g−1 for LIBs and 460 mA h g−1 for SIBs at 0.2 C after 300 cycles, 1C≈372 mA h g−1) and excellent long‐term stability. Structural analysis indicates that the CNFs‐supported porous structure and internal GQDs with excellent electrical conductivity contribute significantly to the dominant capacitive storage mechanism in LPC. This work provides new perspectives for developing advanced carbon‐based materials for multifunctional batteries with improved stability and utilization of porous carbon frameworks during cycles. [ABSTRACT FROM AUTHOR]

Underwater optical communication (UOC) has attracted considerable interest in the continuous expansion of human activities in marine/ocean environments. The water‐durable and self‐powered photoelectrodes that act as a battery‐free light receiver in UOC are particularly crucial, as they may directly face complex underwater conditions. Emerging photoelectrochemical (PEC)‐type photodetectors are appealing owing to their intrinsic aqueous operation characteristics with versatile tunability of photoresponses. Herein, a self‐powered PEC photodetector employing n‐type gallium nitride (GaN) nanowires as a photoelectrode, which is decorated with an iridium oxide (IrOx) layer to optimize charge transfer dynamics at the GaN/electrolyte interface, is reported. Strikingly, the constructed n‐GaN/IrOx photoelectrode breaks the responsivity‐bandwidth trade‐off limit by simultaneously improving the response speed and responsivity, delivering an ultrafast response speed with response/recovery times of only 2 µs/4 µs while achieving a high responsivity of 110.1 mA W−1. Importantly, the device exhibits a large bandwidth with 3 dB cutoff frequency exceeding 100 kHz in UOC tests, which is one of the highest values among self‐powered photodetectors employed in optical communication system. [ABSTRACT FROM AUTHOR]

In this paper, diamond-based vertical p-n junction diodes with step edge termination are investigated using a Silvaco simulation (Version 5.0.10.R). Compared with the conventional p-n junction diode without termination, the step edge termination shows weak influences on the forward characteristics and helps to suppress the electric field crowding. However, the breakdown voltage of the diode with simple step edge termination is still lower than that of the ideal parallel-plane one. To further enhance the breakdown voltage, we combine a p-n junction-based junction termination extension on the step edge termination. After optimizing the structure parameters of the device, the depletion regions formed by the junction termination extension overlap with that of the p-n junction on the top mesa, resulting in a more uniform electric field distribution and higher device performance. [ABSTRACT FROM AUTHOR]

The elementary electronic‐logic‐gates, performing basic logic functions using electric signals as input, act as a building block of modern digital circuits. Intriguingly, the optoelectronic‐logic‐gates (OLGs), composed of optical devices, are emerging as a new logic platform which enables faster and large‐capacity data transmission and processing by using photons as input. However, the strict operation principle of classic optical devices, for example, the unidirectional photoresponse of the photodetector, restricts the functional enrichment of OLGs. Herein, reprogrammable OLGs in a photoelectrochemical (PEC)‐environment are reported by employing gallium‐nitride semiconductor p–n nanowires as photoelectrodes where bidirectional photocurrent is achieved, leading to the demonstration of various binary OLGs including "NOT", "XOR", and "OR". Strikingly, thanks to the versatile tunability of PEC‐photoelectrodes, the logic function of these OLGs is switchable by simply adjusting programming inputs including light intensity, bias voltage, electrolyte condition, and the physicochemical properties of the nanowire surface. Most importantly, unique ternary OLGs, for example, ternary "OR" gates, can also be realized based on binary ones by just tuning their applied bias for higher logic complexity applications, without changing the device architecture. Such reprogrammable binary and ternary OLGs could provide a new avenue toward next‐generation logic circuits for fast computing and data‐processing in the future. [ABSTRACT FROM AUTHOR]