Simulation of near-infrared photodiode detectors based on β-FeSi_2/4H-SiC heterojunctions

In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide(β-FeSi2) as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type β-FeSi2 absorption layer with a doping concentration of 1×1015cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.     

一种新型双吸收层光探测器的设计和分析

PIN光探测器是光纤通信系统和网络中的关键器件.量子效率和响应带宽是衡量光探测器性能的重要指标,并且这两个参数都与器件的吸收层密切相关.为了提高光探测器的性能,提出了一种新型双吸收层光探测器(即PINIP结构),利用侧腐蚀工艺减小双吸收层光探测器吸收层的结面积.对其性能进行了理论研究,结果表明该器件的量子效率达到了93％,同时响应带宽达到了26 GHz,比传统结构的双吸收层光探测器提高了44％.     

掺杂对2H-MoTe2光电特性影响的第一性原理研究

MoTe₂是一种非空间反演对称性半导体,由线性偏振光照射,在无偏压条件下可以直接产生光电流,但是非常微弱.掺杂可以改变电子能带结构和降低空间反演对称性,从而有效的增强光电流.本文基于非平衡格林函数-密度泛函理论,采用第一性原理,计算了本征、Nb掺杂、Ti掺杂和W掺杂2H-MoTe₂的能带结构、透射谱和光电流.能带结构表明：Nb掺杂使半导体2H-MoTe₂能带穿越费米能级,转变为金属特性;Ti和W掺杂减小了2H-MoTe₂的带隙,能带没有穿越费米能级,依然为半导体.掺杂都降低2H-MoTe₂的反演对称对称性,从本征的D_3h转变为C_s.从而在线偏振光的照射下可以有效的提高2H-MoTe₂的光电流.同时,发现掺杂可以提高单层2H-MoTe₂在低光子能量下的消光比,如Nb和Ti掺杂单层2H-MoTe₂分别在光子能量1.1 eV和1.2 eV处取得39.48和28.48的高消光比...     

两端叠层结构的中长波量子阱红外探测器

采用分子束外延技术生长了两个叠层结构的双色量子阱红外探测器结构,并经过光刻和湿法刻蚀制作成两端结构的量子阱红外探测器单元器件. 通过改变量子阱势垒高度,势阱宽度,掺杂浓度,重复周期数等器件参数,可以使总电压在两个叠层之间产生适当的分布,从而使器件表现出不同的电压响应特点. 光电流谱测量显示,器件1随着外加偏置电压可实现对于中波大气红外窗口(3—5 μm)和长波大气红外窗口(8—12 μm)红外响应的切换,器件2在不同的偏置电压下可以对这两个波段同时做出响应. 本文探讨了两端叠层结构量子阱红外探测器的工作原 关键词： 电压调制 同时响应 量子阱红外探测器 双波段     

Graphene integrated photodetectors and opto-electronic devices — a review

Graphene and other two-dimensional materials have recently emerged as promising candidates for next-generation,high-performance photonics. In this paper, the progress of research into photodetectors and other electro-optical devices based on graphene integrated silicon photonics is briefly reviewed. We discuss the performance metrics, photo-response mechanisms, and experimental results of the latest graphene photodetectors integrated with silicon photonics. We also lay out the unavoidable performance trade-offs in meeting the requirements of various applications. In addition, we describe other opto-electronic devices based on this idea. Integrating two-dimensional materials with a silicon platform provides new opportunities in advanced integrated photonics.     

Recent progress on integrating two-dimensional materials with ferroelectrics for memory devices and photodetectors

Two-dimensional(2D) materials, such as graphene and Mo S2 related transition metal dichalcogenides(TMDC), have attracted much attention for their potential applications. Ferroelectrics, one of the special and traditional dielectric materials,possess a spontaneous electric polarization that can be reversed by the application of an external electric field. In recent years, a new type of device, combining 2D materials with ferroelectrics, has been fabricated. Many novel devices have been fabricated, such as low power consumption memory devices, highly sensitive photo-transistors, etc. using this technique of hybrid systems incorporating ferroelectrics and 2D materials. This paper reviews two types of devices based on field effect transistor(FET) structures with ferroelectric gate dielectric construction(termed Fe FET). One type of device is for logic applications, such as a graphene and TMDC Fe FET for fabricating memory units. Another device is for optoelectric applications, such as high performance phototransistors using a graphene p-n junction. Finally, we discuss the prospects for future applications of 2D material Fe FET.     

p-GaN层厚度对GaN基p-i-n结构紫外探测器性能的影响

研究了p-GaN层厚度对GaN基pin结构紫外探测器性能的影响.模拟计算表明：较厚的p-GaN层会减小器件的量子效率,然而同时也会减小器件的暗电流,较薄的p-GaN层会增加器件的量子效率,但是同时也增加了器件的暗电流.进一步的分析表明,金属和p-GaN之间的结电场是出现这种现象的根本原因.在实际的器件设计中,应该根据实际需要选择p型层的厚度. 关键词： GaN 紫外探测器 量子效率 暗电流     

Effect of surface oxygen vacancy defects on the performance of ZnO quantum dots ultraviolet photodetector

The slower response speed is the main problem in the application of ZnO quantum dots (QDs) photodetector, which has been commonly attributed to the presence of excess oxygen vacancy defects and oxygen adsorption/desorption processes. However, the detailed mechanism is still not very clear. Herein, the properties of ZnO QDs and their photodetectors with different amounts of oxygen vacancy (V_O) defects controlled by hydrogen peroxide (H₂O₂) solution treatment have been investigated. After H₂O₂ solution treatment, V_O concentration of ZnO QDs decreased. The H₂O₂ solution-treated device has a higher photocurrent and a lower dark current. Meanwhile, with the increase in V_O concentration of ZnO QDs, the response speed of the device has been improved due to the increase of oxygen adsorption/desorption rate. More interestingly, the response speed of the device became less sensitive to temperature and oxygen concentration with the increase of V_O defects. The findings in this work clarify that the surface V_O defects of ZnO QDs could enhance the photoresponse speed, which is helpful for sensor designing.     

基于PdSe2/GaAs异质结的高灵敏近红外光伏型探测器的制备和图像传感的应用

本文制备了一种基于PdSe₂/GaAs异质结的高灵敏近红外光电探测器,该探测器是通过将多层PdSe₂薄膜转移到平面GaAs上制成的. 所制备的PdSe₂/GaAs异质结器件在808 nm光照下表现出明显的光伏特性,这表明近红外光电探测器可以用作自驱动器件. 进一步的器件分析表明,这种杂化异质结在零偏电压和808 nm光照下具有1.16×10⁵的高开关比. 光电探测器的响应度和比探测度分别约为171.34 mA/W和2.36×10¹¹ Jones. 而且,该器件显示出优异的稳定性和可靠的重复性. 在空气中2个月后,近红外光电探测器的光电特性几乎没有下降,这归因于PdSe₂的良好稳定性. 最后,基于PdSe₂/GaAs的异质结器件还可以用作近红外光传感器.     

A broadband self-powered UV photodetector of aβ-Ga2O3/γ-CuI p–n junction

The symmetric Ti/Au bi-layer point electrodes have been successfully patterned on theβ-Ga;O;films which are prepared by metal–organic chemical vapor deposition(MOCVD)and theγ-Cu I films which are prepared by spin-coating.The fabricated heterojunction has a large open circuit voltage(Voc)of 0.69 V,desired for achieving self-powered operation of a photodetector.Irradiated by 254-nm ultraviolet(UV)light,when the bias voltage is-5 V,the dark current(Idark)of the device is 0.47 p A,the photocurrent(Iphoto)is-50.93 n A,and the photo-to-dark current ratio(Iphoto/Idark)reaches about 1.08×10;.The device has a stable and fast response speed in different wavelengths,the rise time(τr)and decay time(τd)are 0.762 s and 1.741 s under 254-nm UV light illumination,respectively.While theτr andτd are 10.709 s and7.241 s under 365-nm UV light illumination,respectively.The time-dependent(I–t)response(photocurrent in the order of10-10 A)can be clearly distinguished at a small light intensity of 1μW·cm;.The internal physical mechanism affecting the device performances is discussed by the band diagram and charge carrier transfer theory.