Lateral‐Polarity Structure of AlGaN Quantum Wells: A Promising Approach to Enhancing the Ultraviolet Luminescence

Aluminum‐gallium‐nitride alloys (Al _x Ga_{1– x} N, 0 ≤ x ≤ 1) can emit light covering the ultraviolet spectrum from 210 to 360 nm. However, these emitters have not fulfilled their full promise to replace the toxic and fragile mercury UV lamps due to their low efficiencies. This study demonstrates a promising approach to enhancing the luminescence efficiency of AlGaN multiple quantum wells (MQWs) via the introduction of a lateral‐polarity structure (LPS) comprising both III and N‐polar domains. The enhanced luminescence in LPS is attributed to the surface roughening, and compositional inhomogeneities in the N‐polar domain. The space‐resolved internal quantum efficiency (IQE) mapping shows a higher relative IQE in N‐polar domains and near inversion domain boundaries, providing strong evidence of enhanced radiative recombination efficiency in the LPS. These experimental observations are in good agreement with the theoretical calculations, where both lateral and vertical band diagrams are investigated. This work suggests that the introduction of the LPS in AlGaN‐based MQWs can provide unprecedented tunability in achieving higher luminescence performance in the development of solid state light sources.     

High Hall Mobility P‐type Cu2SnS3‐Ga2O3 with a High Work Function

A new transparent p‐type oxide semiconductor (POS) is reported, Cu₂SnS₃‐Ga₂O₃, having high Hall mobility of 36.22 cm² V⁻¹s⁻¹, and high work function of 5.17 eV. The existence of Cu₂SnS₃ and Ga₂O₃ phases in the film is confirmed by X‐ray photoelectron spectroscopy results and the Cu₂SnS₃ shows polycrystalline structure according to Raman spectrum and X‐ray diffraction analysis. The transparent Cu₂SnS₃‐Ga₂O₃ exhibits the carrier concentration of 5.86 × 10¹⁶ cm⁻³, and electrical resistivity of 1.94 Ω·cm. The transparent POS is applied to green quantum light‐emitting diodes (QLEDs) as a hole injection layer (HIL) because of its high work function. The QLED exhibits the maximum current efficiency of 51.72 cd A⁻¹, power efficiency of 31.97 lm W⁻¹, and external quantum efficiency (EQE) of 14.93%, which are much higher than the QLED using polyethylene dioxythophene:poly(styrenesulfonate) HIL exhibiting current efficiency of 42.66 cd A⁻¹, power efficiency of 20.33 lm W⁻¹, and EQE of 12.36%. The Cu₂SnS₃‐Ga₂O₃ developed in this work can be widely used as a transparent and conductive p‐type oxide for thin‐film devices.     

领头项相干态的振幅平方压缩特性

证明了领头项相干态振幅平方压缩的存在,并给出了存在的条件,为进一步认识领头项相干态具有的非经典特性提供了重要的补充和证明。     

无能级稳定判据的多尺度量子谐振子算法

多尺度量子谐振子算法是一种基于量子理论构建的智能优化算法。能级稳定过程是该算法的核心迭代过程之一,能级稳定判据是判断算法是否达到暂稳态的条件。通过对算法物理模型的分析,可知算法在初始采样阶段每一次迭代操作都是能级下降的过程,所以取消能级稳定判据,也可实现算法从高能态过渡到暂稳态直至基态的进化过程。无能级稳定判据的算法在6个标准测试函数上的结果显示其在求解精度、成功率、迭代次数上均表现出了优异的性能,算法的波函数显示无能级稳定判据的算法仍然可以完成从高能态到基态的收敛,且算法在结构上更加简洁,易用性更高,实现难度更低。无能级稳定判据的多尺度量子谐振子算法能够以更加简洁且有效的方式进行应用。     

Identification of the source of an interferer by comparison with known carriers using a single satellite

We describe a method for identifying the source of a satellite interferer using a single satellite. The technique relies on the fact that the strength of a carrier signal measured at the downlink station varies with time due to a number of factors, and we use a quantum‐inspired algorithm to compute a “signature” for a signal, which captures part of the pattern of variation that is a characteristic of the uplink antenna. We define a distance measure to numerically quantify the degree of similarity between two signatures, and by computing the distances between the signature for an interfering carrier and the signatures of the known carriers being relayed by the same satellite at the same time, we can identify the antenna that the interferer originated from, if a known carrier is being relayed from it. As a proof of concept, we evaluate the performance of the technique using a simple statistical model applied to measured carrier data.     

Quantum‐Tunneling Metal‐Insulator‐Metal Diodes Made by Rapid Atmospheric Pressure Chemical Vapor Deposition

A quantum‐tunneling metal‐insulator‐metal (MIM) diode is fabricated by atmospheric pressure chemical vapor deposition (AP‐CVD) for the first time. This scalable method is used to produce MIM diodes with high‐quality, pinhole‐free Al₂O₃ films more rapidly than by conventional vacuum‐based approaches. This work demonstrates that clean room fabrication is not a prerequisite for quantum‐enabled devices. In fact, the MIM diodes fabricated by AP‐CVD show a lower effective barrier height (2.20 eV) at the electrode–insulator interface than those fabricated by conventional plasma‐enhanced atomic layer deposition (2.80 eV), resulting in a lower turn on voltage of 1.4 V, lower zero‐bias resistance, and better asymmetry of 107.     

Cancer‐Targeting Graphene Quantum Dots: Fluorescence Quantum Yields,Stability, and Cell Selectivity

Folic acid, due to its high affinity toward folate receptors (FR), is recognized as one of the most promising cancer targeting vectors. However, the inherent defects of low water solubility (1.6 µg mL^?1), high sensitivity toward photo‐bleaching, low fluorescent quantum yields (QYs, <0.5%) seriously limit its practical application. Herein, ultrastable, highly luminescent graphene quantum dots (GQDs) that selectively target diverse cancer cells are prepared and tested. The new GQDs present step changes compared to common folic acid through an ≈6250 times increase in water solubility (to ≈10 mg mL^?1), more than 150 times in QYs (up to ≈77%), while maintaining luminescence stability up to 98% when subjected to UV, visible light, and heating over 360 min. It is shown that the suppression of nonradiative transitions by amino groups pyrolyzed from pterin plays a key role in the mechanism of high QYs and excellent stability. The functional groups that are likely responsible for the selective targeting of cancer cells with different levels of folate receptor expression on the surface are identified. Collectively with these promising properties, the new functional graphene quantum dots may open a new avenue for cancer diagnosis, drug delivery, and therapies.     

Shallow and Undoped Germanium Quantum Wells: A Playground for Spin and Hybrid Quantum Technology

Buried‐channel semiconductor heterostructures are an archetype material platform for the fabrication of gated semiconductor quantum devices. Sharp confinement potential is obtained by positioning the channel near the surface; however, nearby surface states degrade the electrical properties of the starting material. Here, a 2D hole gas of high mobility (5 × 10⁵ cm² V^?1 s^?1) is demonstrated in a very shallow strained germanium (Ge) channel, which is located only 22 nm below the surface. The top‐gate of a dopant‐less field effect transistor controls the channel carrier density confined in an undoped Ge/SiGe heterostructure with reduced background contamination, sharp interfaces, and high uniformity. The high mobility leads to mean free paths ≈ 6 µm, setting new benchmarks for holes in shallow field effect transistors. The high mobility, along with a percolation density of 1.2 × 10¹¹cm^?2, light effective mass (0.09m_e), and high effective g‐factor (up to 9.2) highlight the potential of undoped Ge/SiGe as a low‐disorder material platform for hybrid quantum technologies.