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Journal of Semiconductors 2011年第8期32卷 33-39页

作者：陈斌杨银堂柴常春宋坤马振洋 Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian University

A two-dimensional model of a 4H-SiC metal-semiconductor-metal（MSM） ultraviolet photodetector has been established using a self-consistent numerical calculation *** structure-dependent spectral response of a 4H-SiC MSM detector is calculated by solving Poisson＇s equation,the current continuity equation and the current density *** calculated results are verified with experimental *** consideration of the reflection and absorption on the metal contacts,a detailed study involving various electrode heights（H）,spacings （S） and widths（W） reveals conclusive results in device *** mechanisms responsible for variations of responsivity with those parameters are *** findings show that responsivity is inversely proportional to electrode height and is enhanced with an increase of electrode spacing and *** addition,the ultraviolet （UV）-to-visible rejection ratio is *** optimizing the device structure at 10 V bias,a responsivity as high as 180.056 mA/W,a comparable quantum efficiency of 77.93%and a maximum UV-to-visible rejection ratio of 1875 are achieved with a detector size of H = 50 nm,S =9μm and W = 3μm.

关键词： MSM structure ultraviolet photodetector spectral response

Analysis of the spectral response of flourishing-withering vegetation changes based on ground spectral measurements

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Science China Earth Sciences 2007年第S1期50卷 86-96页

作者： Guli·Japper Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences ürümqi 830011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

A structural mode was used to characterize vegetation composition at the plant leaf level and a flourishing-withering ratio was developed. The spectral responses of vegetation with different flourishing-withering ratios were analyzed, the change rates of the chlorophyll and moisture content indices of vegetation with different flourishing-withering ratios were compared, and correlations between the chlorophyll and moisture content indices were analyzed. The results reveal that leaves with an inter-mediate flourishing-withering ratio can increase the absorption signatures of vegetation and that band ranges of 570―700 nm and 1300―1540 nm can play a role in indicating changes in the flourishing-withering ratios of vegetation; NPQI, NPCI, R695/R420, R695/R760, R750/R700, the peak-value area of red selvedge, the red selvedge amplitude, the ratio between the red selvedge amplitude and the minimum amplitude, and the NDVI of vegetation change regularly with the change in flourishing-withering ratios, and these nine vegetation indices are highly related to the chlorophyll content. Vegetation indexes of NDWI and PRI are very sensitive to the flourishing-withering change in vegetation and are closely related to the moisture content, and the correlation coefficient is higher than 0.9. The derivative of the spectra is more effective in describing changes in the structural mode of vegetation with different flourishing-withering ratios, especially at band ranges of 552―628 nm and 630―686 nm, and it is more sensitive to the mixed flourishing-withering ratios of leaves rather than to the vegetation indices. The red selvedge position in the spectrum is highly related to the chlorophyll content and is not sensitive to changes in the structural mode of mixed flourishing-withering leaves. The red selvedge parameters are sensitive to changes in the flourishing-withering ratio at the peak-value area of the red selvedge amplitude and the ratio between the red selvedge amplitude and the min

关键词： spectrometer reflectivity flourishing-withering ratio spectral response chlorophyll vegetation index

A simulation of doping and trap effects on the spectral response of AlGaN ultraviolet detectors

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Journal of Semiconductors 2012年第3期33卷 20-23页

作者： Sidi Ould Saad Hamady LMOPS University Paul Verlaine-Metz and SUPELEC-2 Rue Edouard Belin57070 MetzFrance

We study,by means of numerical simulation,the impact of doping and traps on the performance of the＂solar blind＂ultraviolet Schottky detector based on *** implemented physical models and AlGaN material properties taken from the literature,or from the interpolation between the binary materials（GaN and AlN） weighted by the mole *** found that doping and traps highly impact the spectral response of the device,and in particular a compromise in the doping concentration must be reached in order to optimize the spectral response of the *** results give us a powerful tool to quantitatively understand the impact of elaboration and processing conditions on photodetector characteristics,and thus identify the key issues for the development of the technology.

关键词： simulation AlGaN ultraviolet detector spectral response

A Flat spectral response AWG Demultiplexer Composed of Slabs with Islands and Peninsulas

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光学学报 2003年第S1期23卷 157-158页

作者： Yutaka Natsume Junji Yamauchi Ryoichi Tazawa Koji Ishikawa Shigeru Kawaguchi Yuichi Yamamoto Hisamatsu Nakano R & D Department NHK Spring Co. Ltd. 3-10 Fukuura Kanazawa-ku Yokohama 236-0004 Japan Faculty of Engineering Hosei University 3 -7-2 Kajino-cho Koganei Tokyo 184-8584 Japan

Phase adjustment elements called islands and peninsulas are introduced to obtain an AWG demultiplexer with a flat spectral response. Use of the peninsulas enables us to achieve a IdB bandwidth of 0.5 nm.

关键词： spectral response

Study on the spectral response of the Schottky photodetector of GaN

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Chinese Physics B 2006年第6期15卷 1325-1329页

作者：何政亢勇汤英文李雪方家熊 State Key Laboratory of Transducer Technology Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 China Graduates School of Chinese Academy of Sciences Beijing 100039 China

The Schottky photodetector was fabricated on GaN epilayers grown by metalorganic chemical vapour deposition （MOCVD）. The spectral response of the Schottky photodetector was characterized. A new model is proposed to interpret the characteristic of the spectral response curve of the Schottky photodetectors by introducing a penetrating distance of an incident light at a certain wavelength in the current continuity equation and the interface recombination at the metal-semiconductor rectifying contact. The expressions for the spectral response of the Schottky photodetector are deduced and used successfully to fit the experimental data.

关键词： spectral response Schottky photodetector GaN

Numerical Simulation of spectral response for 650 nm Silicon Photodetector

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Semiconductor Photonics and Technology 2003年第2期9卷 82-88页

作者： LIU Li-na, CHEN Chao, LIU Cai-hong(Dept.of Phy.,Xiamen University,Xiamen 361005,CHN) Dept. of Phy. .Xiamen University Xiamen 361005

The theoretical spectral response formula of the N+-N-I-P+ silicon photodetector with high/low emission junction is given. At the same time, considering the process requirements, the optimum structure parameters of silicon photodetector are obtained by numerical calculation and simulation. Under the condition of these optimum structure parameters, the responsivity of the silicon photodetector will be 0.48 A/W at 650 nm.

关键词： spectral response silicon photodetector

Estimation of spectral responses and chlorophyll based on growth stage effects explored by machine learning methods

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The Crop Journal 2022年第5期10卷 1292-1302页

作者： Dehua Gao Lang Qiao Lulu An Ruomei Zhao Hong Sun Minzan Li Weijie Tang Nan Wang Key Laboratory of Modern Precision Agriculture System Integration Research Ministry of EducationChina Agricultural UniversityBeijing 100083China Key Laboratory of Agricultural Information Acquisition Technology Ministry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100083China Yantai Institute of China Agricultural University Yantai 264670ShandongChina

Estimation of leaf chlorophyll content(LCC) by proximal sensing is an important tool for photosynthesis evaluation in high-throughput phenotyping. The temporal variability of crop biochemical properties and canopy structure across different growth stages has great impacts on wheat LCC estimation, known as growth stage effects. It will result in the heterogeneity of crop canopy at different growth stages, which would mask subtle spectral response of biochemistry variations. This study aims to explore spectral responses on the growth stage effects and establish LCC models suited for different growth stages. A total number of 864 pairwise samples of wheat canopy spectra and LCC values with 216 observations of each stage were sampled at the tillering, jointing, booting and heading stages in 2021. Firstly, statistical analysis of LCC and spectral response presented different distribution traits and typical spectral variations peak at 470, 520 and 680 nm. Correlation analysis between LCC and reflectance showed typical red edge shifts. Secondly, the testing model of partial least square(PLS) established by the entire datasets to validate the predictive performance at each stage yielded poor LCC estimation accuracy. The spectral wavelengths of red edge(RE) and blue edge(BE) shifts and the poor estimation capability motivated us to further explore the growth stage effects by establishing LCC models at respective growth ***, competitive adaptive reweighted sampling PLS(CARS-PLS), decision tree(DT) and random forest(RF) were used to select sensitive bands and establish LCC models at specific stages. Bayes optimisation was used to tune the hyperparameters of DT and RF regression. The modelling results indicated that CARS-PLS and DT did not extract specific wavelengths that could decrease the influences of growth stage effects. From the RF out-of-bag(OOB) evaluation, the sensitive wavelengths displayed consistent spectral shifts from BE to GP and from RE to RV from t

关键词： Wheat chlorophyll content Growth stage effects Sensitive wavelengths spectral response Random forest

-lyperspectral response： Key for Mapping Coral Rubber, .ive and Dead Corals

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Journal of Shipping and Ocean Engineering 2012年第3期2卷 182-190页

作者： Nurjannah Nurdin Teruhisa Komatsu Hiroya Yamano Gulam Arafat Chair Rani Awaludin Noer Marine Science Department Hasanuddin University Makassar 95245 Indonesia AORI （Atmosphere and Ocean Research Institute） University of Tokyo Kashiwa 277-8564 Japan National Institute for Environmental Studies Ibaraki 305-8506 JapanHiroya Yamano：Hiroya Yamanot

Measurement, data collection, and analyzing statistically the spectral response of different bottom types are all important steps in mapping shallow water bottom types with remote sensing. Five small islands in the Spermonde archipelago, South Sulawesi, in Indonesia, were selected to measure the reflectance spectral of benthic communities. The objective of this study was to determine optical properties of the live corals, dead corals covered with algae, coral rubber covered with algae, broken shell, sand, seagrass and macro algae. Pearson correlation coefficient and cluster analysis were used to determine spectral similarity in and among coral species based on spectral responses at observed wavelengths and to examine the similarities between the categories. Several benthic communities appear to be highly correlated with one another when the entire spectrum is considered, which may lead to classification errors. Porites meyeri, dead corals and coral rubber （〉 3 months ago） share a high degree of similarity in reflectance. The other coastal benthic communities are readily discriminated.

关键词： spectral response live and dead corals coral rubber benthic communities.

Organic-inorganic hybrid Sn-based perovskite photodetectors with high external quantum efficiencies and wide spectral responses from 300 to 1000 nm

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Science China Materials 2019年第6期62卷 790-796页

作者： Yukun Wang Dezhi Yang Dongge Ma Dong Ha Kim Tansir Ahamad Saad M. Alshehri Agafbnv Vadim Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of Technology Department of Chemistry and Nano Science Ewha Womans University Department of Chemistry College of ScienceKing Saud University Moscow Institute of Physics and Technology Dolgoprudny

Organic-inorganic hybrid perovskites are ideal materials for photodetection owing to their high charge carrier mobility, long charge carrier diffusion length, low dark current density and sharp absorption edge. However, a relatively small band gap(1.6 e V) limits their photonharvesting efficiency in the near-infrared region. In the present work, we demonstrate a hybrid methylamine iodide and Pb-Sn binary perovskite as the light absorption layer in photodetectors. Experimentally, the wavelength of photoresponse onset for the photodetectors can be extended to as great as 1,000 nm when the Sn content of the hybrid perovskite is increased to 30 mol%. In addition, the photodetectors exhibit a photoresponsivity of 0.39 A W^-1, a specific detectivity of 7×10^12 Jones, a fast photoresponse with rise and decay time constants and an external quantum efficiency greater than 50% in the wavelength range of350–900 nm, with a maximum value of about 80% at 550 nm.

关键词： organic-inorganic hybrid perovskite photodetector external quantum efficiency spectral response specific detectivity

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

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Chinese Physics B 2013年第3期22卷 447-452页

作者：蒲红斌贺欣全汝岱曹琳陈治明 Department of Electronic Engineering Xi'an University of Technology

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 *** optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room *** results show that the photodetector has a good rectifying character and a good response to near-infrared *** states should be minimized to obtain a lower reverse leakage *** 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 μ*** illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 *** 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.

关键词： β-FeSi2/4H-SiC near-infrared photodetector spectral response