检索结果-南通市图书馆

Investigation of operation and degradation mechanisms in ZnTeSe blue quantum-dot light-emitting diodes by identifying recombination zone

在线全文

学校读者我要写书评

暂无评论

Nano research 2024年第7期17卷 6527-6533页

作者： Oul Cho Sujin Park Hogeun Chang Jiwhan Kim Jaekwon Kim Sungwoo Kim Taehyung Kim Jeonghun Kwak Department of Electrical and Computer Engineering Inter-university Semiconductor Research Centerand Soft Foundry InstituteSeoul National UniversitySeoul 08826Republic of Korea Material research Center Samsung Advanced Institute of TechnologySuwonGyeonggi-do 16419Republic of Korea

ZnTeSe quantum dots(QDs),recognized as promising eco-friendly blue electroluminescent emitters,remain under-explored in light-emitting diode(LED)***,to elucidate the operation and degradation mechanisms of ZnTeSe blue QD-LEDs,stacked ZnTeSe QD layers with discernable luminescence are designed by varying Te doping concentrations,and the recombination zones(RZs)of the blue QD-LEDs are *** RZs are identified near the hole-transport layer(HTL),confirmed by angular-dependent electroluminescence measurements and optical *** addition,in order to investigate carrier dynamics in the process of recombination,the transient electroluminescence(tr-EL)signals of the dichromatic QD-LEDs are *** a result,it is inferred that the RZ initially formed near the electron-transport layer(ETL)due to the high injection barriers of ***,due to the fast electron mobility,the RZ shifts toward the HTL as the operating current *** the device lifetime tests,the RZ remains stationary while the photoluminescence(PL)corresponding to the RZ undergoes a substantial decrease,indicating that the degradation is accelerated by the concentrated *** this study contributes to a deeper understanding of the operational mechanisms of ZnTeSe blue QD-LEDs.

关键词： quantum dots light-emitting diodes degradation recombination zones carrier dynamics

Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： Se Hyun Kim Younghwan Lee Dong Hyun Lee Geun Hyeong Park Hyun Woo Jeong Kun Yang Yong Hyeon Cho Young Yong Kim Min Hyuk Park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea inter-university semiconductor research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization

Rational molecular design of efficient yellow-red dendrimer TADF for solution-processed OLEDs: a combined effect of substitution position and strength of the donors

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第5期67卷 1613-1623页

作者： Changfeng Si Dianming Sun Tomas Matulaitis David B.Cordes Alexandra M.Z.Slawin Eli Zysman-Colman Organic semiconductor centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsKY169STUK

The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.

关键词： thermally activated delayed fluorescence solution-processing red OLEDs dibenzo[a,c]phenazine dendrimers

How optimized emitter design leads to saturated color highperformance organic light-emitting diodes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第1期67卷 314-315页

作者： Eli Zysman-Colman Organic semiconductor centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsFifeKY169STUK

In an article recently published in *** Chem.,Liao,Jiang,and their co-workers[1]report two N/carbonyl-based multi-resonant thermally activated delayed fluorescence(MR-TADF)emitters,the organic light-emitting diode(OLED)that uses one of these,MTDMQAO,showed record maximum external quantum efficiencies(EQEmax)for devices using this class of *** reason for this impressive device performance stems from a rationale and judicious molecular design,building on a core QAO(aka DiKTa)[2]MR-TADF emitter structure that the authors helped to pioneer[3,4],and decorating a fused derivative of it with an electron-withdrawing triazine unit.

关键词： emitter diodes saturated

Demonstration of normally-off p-channel GaN transistor with high threshold voltage and low subthreshold swing based on single p-GaN

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第9期67卷 348-349页

作者： Yangfeng LI Zian DONG Shuai CHEN Qin WANG Tong LI Shulin CHEN Kun ZHENG Jie ZHANG Guojian DING Yang WANG Haiqiang JIA Rong YANG Lei LIAO Changsha semiconductor Technology and Application Innovation research Institute College of Semiconductors (College of Integrated Circuits) Hunan University Hunan San'an semiconductor Co. Ltd. Songshan Lake Materials Laboratory

GaN outperforms silicon in applications with high power and high frequency owing to the high critical electric field and high electron mobility. However, the hole-based GaN transistors which are pivotal to the GaN-based CMOS circuits and high-side switching are still under investigation. Two-dimensional hole gas(2DHG) has been used to demonstrate the p-channel GaN field-effect-transistors(FETs) [1–5].

关键词： MOSFETS

Entropy variances of pure coherent states in the diffusion channel

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第9期33卷 384-388页

作者： Wei-Feng Wu Yong Fang Peng Fu School of Mechanical and Electrical Engineering Chizhou UniversityChizhou 247000China Anhui research Center of semiconductor Industry Generic Technology Chizhou 247000China

Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum representation ofits analytical solution. we find that the pure coherent states evolve into the new mixed thermal superposed states in thediffusion channel. Also, we investigate the statistical properties of the initial coherent states and their entropy evolutions inthe diffusion channel, and find that the entropy evolutions are only related to the decay time and without the amplitudes ofthe initial coherent states.

关键词： entangled state representation diffusion channel coherent state entropy evolution

Long Term X-Ray Spectral Variations of the Seyfert-1 Galaxy Mrk 279

在线全文

学校读者我要写书评

暂无评论

research in Astronomy and Astrophysics 2024年第6期24卷 307-314页

作者： K.Akhila Ranjeev Misra Savithri H.Ezhikode K.Jeena Department of Physics Providence Women’s CollegeUniversity of CalicutKerala 673009India inter-university centre for Astronomy and Astrophysics(IUCAA) PB No.4GaneshkhindPune 411007India Department of Physics and Electronics CHRIST(Deemed to be University)Hosur Main RoadBangalore 560029India

We present the results from a long term X-ray analysis of Mrk 279 during the period 2018–*** use data from multiple missions–AstroSat,NuSTAR and XMM-Newton,for the *** X-ray spectrum can be modeled as a double Comptonization along with the presence of neutral Fe Kαline emission,at all *** determined the source’s X-ray flux and luminosity at these different *** find significant variations in the source’s flux *** also investigate the variations in the source’s spectral components during the observation *** find that the photon index and hence the spectral shape follow the variations only over longer time *** probe the correlations between fluxes of different bands and their photon indices,and found no significant correlations between the parameters.

关键词： galaxies:Seyfert galaxies:individual(Mrk 335) X-rays:galaxies

Highly responsive broadband Si-based MoS2 phototransistor on high-k dielectric

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第6期67卷 180-189页

作者： Ali IMRAN Xin HE Jiwei LIU Qinghai ZHU Muhammad SULAMAN Fei XUE Mingsheng XU Deren YANG College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University ZJU-Hangzhou Global Scientific and Technological Innovation centre School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of Technology

The demand for photodetectors and image sensors has grown exponentially in the past decade in biomedical, security surveillance, robotics, automotive, quality control, image recognition, and military applications, due to their superior quality, broadband detection, lower noise, and economic viability. Here,we report a MoS2channel-based phototransistor over an HfO2/n-Si substrate isolated by an h BN layer. The high photoresponse is achieved through the integration of the photoconduction, photogating, and mobility enhancement process by utilizing excellent features of MoS2, HfO2/Si, and h BN. The capacitive coupling of the photogenerated carriers by high-k dielectric HfO2leads to modulation of MoS2Fermi level due to electrostatic doping. Furthermore, the MoS2also contributes to the photogeneration of carriers due to its semiconducting nature, leading to additional photocurrent. Ultimately, the combination of photogating,photoconduction, and swift carrier extraction with remarkable mobility of 11.65 cm2· V-1· s-1results in high responsivity, external quantum efficiency, and detectivity of 4.5 × 10～8A · W-1, 0.72 × 10～6, and 6.20× 1016Jones at 266 nm illumination, respectively. The device also demonstrates broadband photoresponse from 266–1000 nm wavelengths. The high responsivity distinguishes the potential of our device for the future of optoelectronics and broadband image sensing applications.

关键词： photogating photoconduction two-dimensional materials high $~k$ dielectric carrier scattering phototransistor

Progress on the program of Si-compatible two-dimensional semiconductor materials and devices

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第6期67卷 152-171页

作者： Mingsheng XU Yuwei WANG Jiwei LIU Deren YANG College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University

Two-dimensional(2D) materials are at the forefront of innovation, heralding a new era for nextgeneration electronics and optoelectronics. These materials are distinguished by their unique structural characteristics: they have no hanging bonds on their surface, exhibit weakened electrostatic shielding in the Z-direction, and boast atomic thickness in their monolayers. These features have led to groundbreaking discoveries in electrical, optical, and magnetic properties, paving the way for advancements in low-power electronics, valleytronics, infrared detectors, and memory devices. Despite these promising developments,Si-based technologies continue to dominate the landscape of next-generation electronics and optoelectronics,as well as heterogeneous integration. In response to this ongoing evolution, the National Natural Science Foundation of China(NSFC) initiated a major program in 2021 dubbed “Si-compatible two-dimensional semiconductor materials and devices”. This study reviews the progress made under the NSFC Program,spotlighting its main achievements and outlining key future research directions. Additionally, it sheds light on the challenges that researchers in the 2D domain face, particularly in developing Si-compatible 2D technologies.

关键词： two-dimensional materials Si-based CMOS technologies electronics and optoelectronics heterogeneous integration low-power