Realization of flexible in-memory computing in a van der Waals ferroelectric heterostructure tri-gate transistor

Combining logical function and memory characteristics of transistors is an ideal strategy for enhancing computational efficiency of transistor devices.Here,we rationally design a tri-gate two-dimensional(2D)ferroelectric van der Waals heterostructures device based on copper indium thiophosphate(CuInP_(2)S_(6))and few layers tungsten disulfide(WS_(2)),and demonstrate its multi-functional applications in multi-valued state of data,non-volatile storage,and logic operation.By co-regulating the input signals across the tri-gate,we show that the device can switch functions flexibly at a low supply voltage of 6 V,giving rise to an ultra-high current switching ratio of 107 and a low subthreshold swing of 53.9 mV/dec.These findings offer perspectives in designing smart 2D devices with excellent functions based on ferroelectric van der Waals heterostructures.

Ta_(2)NiSe_(5)/GaN范德华异质结用于具有超高响应性和耐恶劣环境的紫外光电探测器

氮化镓由于其直接带隙、固有的紫外吸收和高击穿电压引起了人们对其在紫外光电探测领域的极大研究兴趣.在本工作中,我们成功地将新型三元硫族化合物Ta_(2)NiSe_(5)与非故意掺杂的GaN堆叠,形成了具有典型I型能带排列的混合维度的Ta_(2)NiSe_(5)/GaN(2D/3D)范德瓦尔斯异质结构.该异质结构表现出优异的紫外探测性能(光开关比为10~7,响应度为1.22×10^(4)A W^(-1)).此外,在365 nm的光照和4 V的偏压下,探测度提高至1.3×10^(16)Jones,并表现出1.22/31.6 ms的快速响应速率.值得注意的是,该器件还具有优异的稳定性、可重复性和抗恶劣环境条件(包括高温和酸性条件)的耐受性.得益于光电探测器的高响应度、探测度和光开关比,我们成功地将该异质结构器件集成到紫外光通信中,证明了Ta_(2)NiSe_(5)/GaN光电探测器在信息传输中有着优异的应用前景.

Polarization-sensitive and wide-spectrum photovoltaic detector based on quasi-1D ZrGeTe_(4)nanoribbon

Low-dimensional semiconductors with in-plane anisotropy and narrow bandgap have been extensively applied to polarized detection in the near-infrared(NIR)region.However,the narrow bandgap can cause noise owing to the high dark current in photodetectors.This article reports quasi-1D ZrGeTe_(4)nanoribbonbased photodetectors with low dark current and broadband polarization detection.The photodetector was fabricated by evaporating 50-nm-thick Au electrodes on a ZrGeTe_(4)nanoribbon.Benefiting from the photovoltaic characteristics in the ZrGeTe_(4)nanoribbon and Au electrodes,these photodetectors can operate without bias voltage,with decreased dark current,and improved device performance.Furthermore,the quasi-1D ZrGeTe_(4)nanoribbon-based photodetectors demonstrate a polarization sensitivity in a broadband from visible(VIS)to the NIR region,such as a high photoresponsivity of 625.65 mA W1,large external quantum efficiency of 145.9%at 532 nm,and photocurrent anisotropy ratio of 2.04 at 1064 nm.They exhibit a novel perpendicular optical reversal of 90in polarization-sensitive photodetection,angle-resolved absorption spectra,and azimuth-dependent reflectance difference microscopy(ADRDM)from VIS to the NIR region,as opposed to other nanoribbon-based polarization-sensitive photodetectors.This work paves the way for utilizing photovoltaic photodetectors based on low-dimensional materials for broad-spectrum polarized photodetection.

基于极性可重构WSe_(2)肖特基异质结的非对称逻辑整流器和光电探测器

基于二维材料范德华异质结的自驱动光电探测器是逻辑光电子器件和智能图像传感器的重要组成部分.本文通过机械剥离和干法转移制备了一种底部Au接触的PtSe_(2)/WSe_(2)/Au非对称肖特基光电二极管.栅极可调的Au/WSe_(2)肖特基势垒大小、弱费米钉扎效应、高半金属PtSe_(2)导电率以及良好的PtSe_(2)/WSe_(2)层间耦合效应使得该二极管产生极性可重构现象,可实现栅极可调正负整流行为,且整流比变化范围在10−2到104之间,达到6个量级.我们利用此特性验证了半波逻辑整流器功能.此外,此自驱动器件的最大光响应度达316 mA W^(−1),最大光开关比达105,光电转换效率为4.62%,响应时间仅为830/950μs.光电流微区扫描结果表明,器件的光电流主要分布在Au/WSe_(2)界面边缘,证实该器件为非对称肖特基光电二极管.该器件还实现了高分辨率的可见光单点成像.上述研究结果表明,本工作为制备高性能半波整流器、超快自驱动光电探测器和高分辨图像传感器提供了一种简便有效的策略.

混合1D/2D异质结构耦合电子结构工程用于高灵敏度和偏振依赖的光电探测器

随着光电探测器的广泛应用,人们迫切需要高灵敏度、偏振依赖的光电探测技术.在这一领域,二维二硫化钨(2D WS_(2))表现出出色的光学和电子特性,使其成为一种在光电应用领域有吸引力的光敏材料.但是,2D WS_(2)缺乏有效的内建电场和光电导增益机制,阻碍了其在高性能光电探测器中的应用.在此,我们提出了一种包含1D Te和2D WS_(2)的混合异质结构光电探测器.在该器件中,二维WS_(2)在1D Te上产生平面内形态应变,该应变能调节WS_(2)的局部电子结构,并在水平方向上形成II型能带排列.此外,2D WS_(2)和1D Te的垂直异质结引入了光电导增益.这两种效应优化了光致载流子的转移,使得光电探测器具有较高的灵敏度(光响应度为~27.7 A W^(-1),探测度为9.5×10^(12)Jones,上升/衰减时间为19.3/17.6 ms).此外,该器件还获得了各向异性的光电探测特性,其二向色比可达2.1.这种混合的1D/2D异质结构克服了单种材料固有的局限性,实现了新的性能,为构建多功能光电器件开辟了新的途径.