Optical wireless communication (OWC) using the ultra-broad spectrum of the visible-to-ultraviolet (UV) wavelength region remains a vital field of research for mitigating the saturated bandwidth of radio-frequency (RF) communication. However, the lack of an efficient UV photodetection methodology hinders the development of UV-based communication. The key technological impediment is related to the low UV-photon absorption in existing silicon photodetectors, which offer low-cost and mature platforms. To address this technology gap, we report a hybrid Si-based photodetection scheme by incorporating CsPbBr3 perovskite nanocrystals (NCs) with a high photoluminescence quantum yield (PLQY) and a fast photoluminescence (PL) decay time as a UV-to-visible colour-converting layer for high-speed solar-blind UV communication. The facile formation of drop-cast CsPbBr3 perovskite NCs leads to a high PLQY of up to ~73% and strong absorption in the UV region. With the addition of the NC layer, a nearly threefold improvement in the responsivity and an increase of ~25% in the external quantum efficiency (EQE) of the solar-blind region compared to a commercial silicon-based photodetector were observed. Moreover, time-resolved photoluminescence measurements demonstrated a decay time of 4.5 ns under a 372-nm UV excitation source, thus elucidating the potential of this layer as a fast colour-converting layer. A high data rate of up to 34 Mbps in solar-blind communication was achieved using the hybrid CsPbBr3–silicon photodetection scheme in conjunction with a 278-nm UVC light-emitting diode (LED). These findings demonstrate the feasibility of an integrated high-speed photoreceiver design of a composition-tuneable perovskite-based phosphor and a low-cost silicon-based photodetector for UV communication. A silicon-based receiver that incorporates perovskite nanocrystals efficiently detects ultraviolet signals, paving the way towards high-speed, high-bandwidth UV wireless communication. The photodetector (PD), developed by Boon S. Ooi of King Abdullah University of Science and Technology (KAUST) and colleagues in Saudi Arabia, is less bulky and cheaper to manufacture than currently available receivers. It builds on technologically advanced silicon-based PDs, which are compact and widely available, but respond best to higher wavelength green light. Incorporating cesium lead bromide (CsPbBr3) perovskite nanocrystals into a silicon-based PD facilitated efficient conversion of UV into green light. The team demonstrated that their receiver could be used in high-speed UV-based communication, paving the way for the use of perovskite-based materials in terrestrial and underwater UV-Internet systems.

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High-speed colour-converting photodetector with all-inorganic CsPbBr3 perovskite nanocrystals for ultraviolet light communication

ZnO nanoparticles are still a hot area for research even after ample work has been done by researchers across the world. It is a versatile material for doping of different transition metals among o...

Progress on Transition Metal-Doped ZnO Nanoparticles and Its Application

Cloud computing is a dynamic field of information and communication technologies (ICTs), introducing new challenges for environmental protection. Cloud computing technologies have a variety of application domains, since they offer scalability, are reliable and trustworthy, and offer high performance at relatively low cost. The cloud computing revolution is redesigning modern networking, and offering promising environmental protection prospects as well as economic and technological advantages. These technologies have the potential to improve energy efficiency and to reduce carbon footprints and (e-)waste. These features can transform cloud computing into green cloud computing. In this survey, we review the main achievements of green cloud computing. First, an overview of cloud computing is given. Then, recent studies and developments are summarized, and environmental issues are specifically addressed. Finally, future research directions and open problems regarding green cloud computing are presented. This survey is intended to serve as up-to-date guidance for research with respect to green cloud computing.

https://www.mdpi.com/2073-8994/9/12/295/pdf

Green Cloud Computing: A Literature Survey

We systemically investigated the impact of variation in temperature on electrical parameters for a dual material gate (DMG) FinFET. We have highlighted the DC performance such as drain current characteristics, subthreshold swing (SS), and Ion/Ioff for the variation in temperature from 200 to 350 K. Furthermore, the influence of temperature on RF/Analog parameters like transconductance (gm), output conductance (gd), gate capacitance (CGG), intrinsic delay, transconductance generation factor (TGF = gm/ID), intrinsic gain (gm/gd), cutoff frequency (ft), gain frequency product (GFP), transconductance frequency product (TFP), and gain transconductance frequency product (GTFP) are presented through TCAD simulator. We also discussed the influence of temperature on linearity parameters like gm2, gm3, VIP2, VIP3, IMD3, IIP3, and 1-dB compression point. A comparative study between DMG and single material gate (SMG) FinFET is also investigated.

Temperature effect on RF/analog and linearity parameters in DMG FinFET

In this article, we investigated the impact of temperature variation on DC, analog, RF, and wireless performance of Gate Stack Gate All Around (GS-GAA) FinFET using SILVACO Atlas 3D simulator. The GAA structure introduction enhances the switching ratio (Ion/Ioff) by ∼152.37% and reduces the subthreshold swing (SS) by ∼6.5%. At gate voltage (Vgs) ∼ 0.725 V, the GS-GAA FinFET device exhibits the ZTC (Zero-Temperature-Coefficient) bias point, i.e., the effect of temperature on drain current gets nullified. DC parameters such as leakage current (Ioff), on current (Ion), SS, and threshold voltage (Vth) deteriorate with the rise in temperature. The enhancement in temperature degrades the RF and analog performance of the device by suppressing the parameters like transconductance (gm), device efficiency (TGF), cut-off frequency (fT), gain frequency product (GFP), gain-bandwidth product (GBP), etc. The device’s wireless performance is analyzed using linearity and harmonic distortion parameters such as gm3, gm2, 1-dB compression point, IIP3, VIP3, VIP2, IMD3, HD3, and HD2, and it shows significant improvement as the temperature increases from 300 K to 500 K.

TCAD Temperature Analysis of Gate Stack Gate All Around (GS-GAA) FinFET for Improved RF and Wireless Performance

The most challenging field of concern these days is energy conservation in various applications. Energy crisis led a way to green computing and green computing needs an efficient redesign of algorithms and mechanisms to meet the desired energy efficiency. Green IT is a study and practice which can reduce energy consumption significantly. In this paper various efficient energy saving Green IT methods are discussed. As cloud computing has become a fast emerging technology this days, some energy saving strategy for cloud computing has also been discussed in the paper. Most of the IT sector energy consumption happens in data centers. Virtual Machine migration an emerging energy aware technology used in data centers is also discussed in the paper. Finally some power conserving matrix parameters are given importance.

http://www.sersc.org/journals/IJGDC/vol8_no1/28.pdf

Power Saving Strategies in Green Cloud Computing Systems

This present work emphasizes the numerical modeling of lead-free methylammonium tin tri-iodide (MASnI3)-based perovskite solar cells (PSCs) under optimizing preconditions. The prior selection of the perovskite material of MASnI3 is feasible for a more extended absorption spectrum due to a smaller bandgap of 1.3 eV than higher bandgap methylammonium lead tri-iodide (MAPbI3)-based PSC and the factor of lesser toxicity. Furthermore, to enhance the efficiency of the device, selecting potentially steadier and superior carrier transport materials (CTMs) is among the most effective approaches for optimizing device outputs. Among the proposed materials, a prior selection of copper antimony sulfide (CuSbS2) and zinc oxide (ZnO) as CTMs with an optimized thickness of MASnI3 material has offered a higher power conversion efficiency (PCE) of 22.16% under the photoillumination AM1.5. Furthermore, the less-defective PSC device can also be helpful for further device optimization and futuristic development.

Deboraj Muchahary

Papers

Power Saving Strategies in Green Cloud Computing Systems

Investigation of Carrier Transport Materials for Performance Assessment of Lead-Free Perovskite Solar Cells

Temperature dependent study of Fin-FET drain current through optimization of controlling gate parameters and dielectric material

High-efficiency thin film ZnMgO/ZnO solar cell simulation approach: Temperature dependency, BSF and efficient small signal analysis

A novel graded approach for improving the efficiency of Lead-Free perovskite solar cells