Pub Date : 2020-01-01DOI: 10.3116/16091833/21/2/93/2020
Zinelabiddine Mezache
. A new terahertz square-ring patch antenna is designed basing on a very thin layer of graphene as a radiating patch. It is characterized by multiband operation and can improve the radiation pattern due to its self-similar property or fractal geometry. We analyze a graphene-based square-ring patch placed upon a silicon substrate with the thickness 3.25 µm. The structure has compact dimensions and radiates at a single frequency, 3.62 THz. Our antenna can also consist of a microstrip line to resonate at two (1.913 and 4.294 THz) or three (1.913, 3.167 and 4.260 THz) frequencies. This is achieved by varying the patch shape at the voltage standing-wave ratio less or equal to two. Our calculations are performed using a full-wave electromagnetic simulation based on a standard finite-difference time domain method. Various parameters like the return loss, the voltage standing-wave ratio, the gain and the efficiency are determined for the multiband operation regime.
{"title":"Analysis of multiband graphene-based terahertz square-ring fractal antenna","authors":"Zinelabiddine Mezache","doi":"10.3116/16091833/21/2/93/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/2/93/2020","url":null,"abstract":". A new terahertz square-ring patch antenna is designed basing on a very thin layer of graphene as a radiating patch. It is characterized by multiband operation and can improve the radiation pattern due to its self-similar property or fractal geometry. We analyze a graphene-based square-ring patch placed upon a silicon substrate with the thickness 3.25 µm. The structure has compact dimensions and radiates at a single frequency, 3.62 THz. Our antenna can also consist of a microstrip line to resonate at two (1.913 and 4.294 THz) or three (1.913, 3.167 and 4.260 THz) frequencies. This is achieved by varying the patch shape at the voltage standing-wave ratio less or equal to two. Our calculations are performed using a full-wave electromagnetic simulation based on a standard finite-difference time domain method. Various parameters like the return loss, the voltage standing-wave ratio, the gain and the efficiency are determined for the multiband operation regime.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/3/141/2020
I. Fodchuk, S. Balovsyak, S. Novikov, I. Yanchuk, V. Romankevych
We develop a new approach to the analysis of experimental Moiré patterns obtained with LLL-interferometer. Radial distributions of the energy spectra of Moiré patterns reveal different sensitivities to the sources of local mechanical strains in the lowand high-frequency ranges. This offers new possibilities for determining the magnitudes of total mechanical strains and reconstructing their spatial distributions in crystals.
{"title":"Reconstruction of spatial distribution of strains in crystals using the energy spectrum of X-ray Moire patterns","authors":"I. Fodchuk, S. Balovsyak, S. Novikov, I. Yanchuk, V. Romankevych","doi":"10.3116/16091833/21/3/141/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/3/141/2020","url":null,"abstract":"We develop a new approach to the analysis of experimental Moiré patterns obtained with LLL-interferometer. Radial distributions of the energy spectra of Moiré patterns reveal different sensitivities to the sources of local mechanical strains in the lowand high-frequency ranges. This offers new possibilities for determining the magnitudes of total mechanical strains and reconstructing their spatial distributions in crystals.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"26 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/3/126/2020
M. Khan, A. Almohammedi, W. Farooq
Abstract. Thin films of nanostructured zinc oxide doped with aluminium of different concentrations are synthesized on glass substrates, using a spin-coated sol– gel method. The effect of picosecond-laser irradiation on these thin films is studied using different optical techniques. Their structural and optical properties are investigated using X-ray diffraction, near-visible and infrared absorption spectra and photoluminescence. Optical bandgap values are calculated using a Tauc’s method. Slight variation in the relative intensity of X-ray diffraction and broadening of the lines are observed as a result of laser irradiation that causes some disorder in crystallinity. The relative intensities of the absorption and emission spectra decrease with increasing percentage of aluminium and laser-exposure time. The value of this decrease depends on the dopant concentration. Moreover, the emission reveals a slight red shift. The size of nanocrystals also changes at different Al doping percentages and exposure times. The reduction of the relative intensities mentioned above is attributed to changing nanocrystal sizes and structure of a surface layer.
{"title":"Effect of picosecond-laser irradiation on the properties of nanostructured aluminium-doped zinc oxide thin films","authors":"M. Khan, A. Almohammedi, W. Farooq","doi":"10.3116/16091833/21/3/126/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/3/126/2020","url":null,"abstract":"Abstract. Thin films of nanostructured zinc oxide doped with aluminium of different concentrations are synthesized on glass substrates, using a spin-coated sol– gel method. The effect of picosecond-laser irradiation on these thin films is studied using different optical techniques. Their structural and optical properties are investigated using X-ray diffraction, near-visible and infrared absorption spectra and photoluminescence. Optical bandgap values are calculated using a Tauc’s method. Slight variation in the relative intensity of X-ray diffraction and broadening of the lines are observed as a result of laser irradiation that causes some disorder in crystallinity. The relative intensities of the absorption and emission spectra decrease with increasing percentage of aluminium and laser-exposure time. The value of this decrease depends on the dopant concentration. Moreover, the emission reveals a slight red shift. The size of nanocrystals also changes at different Al doping percentages and exposure times. The reduction of the relative intensities mentioned above is attributed to changing nanocrystal sizes and structure of a surface layer.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"21 1","pages":"126-140"},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/1/26/2020
C. Boonsri, P. Limsuwan, P. Buranasiri
We have measured thermal expansion coefficient of a bulk CaMnO3 thermoelectric module with a cylindrical shape, using a shadow method. The CaMnO3 module has been heated from the room temperature up to 773 K. At each temperature, the shadow image has been recorded by a CMOS camera and reconstructed with a HoloViewer program in MATLAB. Then the diameters of the module have been obtained at different temperatures in the region 300–773 K. Finally, we have determined the linear thermal expansion and the thermal expansion coefficient for CaMnO3. Our results demonstrate that the expansion coefficient for the bulk CaMnO3 thermoelectric module depends linearly on the temperature in the region under study.
{"title":"Determination of thermal expansion coefficient for thermoelectric CaMnO3 with a shadow method","authors":"C. Boonsri, P. Limsuwan, P. Buranasiri","doi":"10.3116/16091833/21/1/26/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/1/26/2020","url":null,"abstract":"We have measured thermal expansion coefficient of a bulk CaMnO3 thermoelectric module with a cylindrical shape, using a shadow method. The CaMnO3 module has been heated from the room temperature up to 773 K. At each temperature, the shadow image has been recorded by a CMOS camera and reconstructed with a HoloViewer program in MATLAB. Then the diameters of the module have been obtained at different temperatures in the region 300–773 K. Finally, we have determined the linear thermal expansion and the thermal expansion coefficient for CaMnO3. Our results demonstrate that the expansion coefficient for the bulk CaMnO3 thermoelectric module depends linearly on the temperature in the region under study.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"21 1","pages":"26-34"},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69615597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/4/191/2020
X. Ren, Y. Qin, L. Qiao
To achieve high-resolution three-dimensional images, a number of imaging methods based on compressive sensing (CS) have been suggested in the recent years for synthetic-aperture radar (SAR) tomography. However, the CS-based methods are sensitive to noise. In this work, we develop a new Bayesian compressive sensing (BCS) imaging method for the SAR tomography. In the framework of BCS, a ‘sparseness’ prior distribution of the imaging scene and an additive noise are properly considered in the imaging process. As a consequence, the BCS-based method under the conditions of low noise levels can provide a better performance than the common norm-based CS methods. The results obtained via simulations of our SAR-tomography imaging method confirm its advantages.
{"title":"Bayesian compressive sensing for synthetic-aperture radar tomography imaging","authors":"X. Ren, Y. Qin, L. Qiao","doi":"10.3116/16091833/21/4/191/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/4/191/2020","url":null,"abstract":"To achieve high-resolution three-dimensional images, a number of imaging methods based on compressive sensing (CS) have been suggested in the recent years for synthetic-aperture radar (SAR) tomography. However, the CS-based methods are sensitive to noise. In this work, we develop a new Bayesian compressive sensing (BCS) imaging method for the SAR tomography. In the framework of BCS, a ‘sparseness’ prior distribution of the imaging scene and an additive noise are properly considered in the imaging process. As a consequence, the BCS-based method under the conditions of low noise levels can provide a better performance than the common norm-based CS methods. The results obtained via simulations of our SAR-tomography imaging method confirm its advantages.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"21 1","pages":"191-200"},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/1/47/2020
O. Krupych, I. Martynyuk-Lototska, A. Say, V. Boyko, V. Goleus, Y. Hordieiev, R. Vlokh
New high-lead glasses with two different compositions are subjected to comprehensive material characterization. In particular, their refractive indices, optical transmission spectra, photo-elastic, piezo-optic and strain-optic constants, ultrasound velocities and elastic constants are measured. We find the shortwavelength absorption edges as λedge = 383 and 475 nm for these compounds. The acousto-optic figures of merit are calculated for the glasses under study. Their maximal acousto-optic figures of merit turn out to be higher than the corresponding values for fused silica and dense flint glasses, which are known as vitreous materials widely used in serial acousto-optic modulators.
{"title":"Characterization of PbO-B2O3-GeO2-La2O3 and PbO-B2O3-SiO2-ZnO glasses: refractive, acoustic, photo-elastic and acousto-optic properties","authors":"O. Krupych, I. Martynyuk-Lototska, A. Say, V. Boyko, V. Goleus, Y. Hordieiev, R. Vlokh","doi":"10.3116/16091833/21/1/47/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/1/47/2020","url":null,"abstract":"New high-lead glasses with two different compositions are subjected to comprehensive material characterization. In particular, their refractive indices, optical transmission spectra, photo-elastic, piezo-optic and strain-optic constants, ultrasound velocities and elastic constants are measured. We find the shortwavelength absorption edges as λedge = 383 and 475 nm for these compounds. The acousto-optic figures of merit are calculated for the glasses under study. Their maximal acousto-optic figures of merit turn out to be higher than the corresponding values for fused silica and dense flint glasses, which are known as vitreous materials widely used in serial acousto-optic modulators.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"21 1","pages":"47-56"},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69615741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/2/103/2020
I. Abbasov, M. Musayev, J. Huseynov, M. Kostyrko, S. Babayev, G. Eyyubov, S. Aliyeva
. We study the photoluminescence in polycrystalline ZnSe synthesized using a chemical vapour-deposition technique, which arises from excitation by the sources of different types and wavelengths. Two experimental geometries are used, which are related to the normal incidence of exciting radiation upon either polished or unpolished ZnSe surfaces. The excitation from the polished surface is carried out by the lasers with the wavelengths λ ex = 335 and 325 nm (i.e., the photon energies higher than the bandgap, hv ex > E g ), semiconductor lasers with λ ex = 532, 642 and 785 nm (i.e., hv ex < E g ) and a xenon lamp. The sample is also excited from the unpolished surface, using the lasers with λ ex = 325 nm ( hv ex > E g ) and λ ex = 532 nm ( hv ex < E g ), as well as the semiconductor laser with λ ex = 532 nm ( hv ex < E g ). Following from our experimental results, we analyze and compare the edge (exciton) luminescence and the impurity-defect luminescence. Different behaviours of the luminescence spectra are observed, which depend on the type of excitation. Instruments) grating 1800 and ANDOR IDUS CCD (DU420-OE respectively them spectral of our
． 本文研究了化学气相沉积法合成的多晶ZnSe在不同类型和波长的光源激发下产生的光致发光。使用了两种实验几何形状，它们与激发辐射在抛光或未抛光的ZnSe表面上的正常入射有关。抛光表面的激发由波长λ ex = 335和325 nm的激光器(即光子能量高于带隙，hv ex = > E g)、λ ex = 532、642和785 nm的半导体激光器(即hv ex < E g)和氙灯进行。利用λ ex = 325 nm (hv ex = > E g)和λ ex = 532 nm (hv ex < E g)激光器以及λ ex = 532 nm (hv ex < E g)半导体激光器从未抛光表面激发样品。根据我们的实验结果，我们分析和比较了边缘(激子)发光和杂质缺陷发光。根据激发类型的不同，观察到不同的发光光谱行为。仪器:光栅1800和ANDOR IDUS CCD (DU420-OE)分别用于我们的光谱
{"title":"Photoluminescence spectra of polycrystalline ZnSe in different experimental geometries","authors":"I. Abbasov, M. Musayev, J. Huseynov, M. Kostyrko, S. Babayev, G. Eyyubov, S. Aliyeva","doi":"10.3116/16091833/21/2/103/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/2/103/2020","url":null,"abstract":". We study the photoluminescence in polycrystalline ZnSe synthesized using a chemical vapour-deposition technique, which arises from excitation by the sources of different types and wavelengths. Two experimental geometries are used, which are related to the normal incidence of exciting radiation upon either polished or unpolished ZnSe surfaces. The excitation from the polished surface is carried out by the lasers with the wavelengths λ ex = 335 and 325 nm (i.e., the photon energies higher than the bandgap, hv ex > E g ), semiconductor lasers with λ ex = 532, 642 and 785 nm (i.e., hv ex < E g ) and a xenon lamp. The sample is also excited from the unpolished surface, using the lasers with λ ex = 325 nm ( hv ex > E g ) and λ ex = 532 nm ( hv ex < E g ), as well as the semiconductor laser with λ ex = 532 nm ( hv ex < E g ). Following from our experimental results, we analyze and compare the edge (exciton) luminescence and the impurity-defect luminescence. Different behaviours of the luminescence spectra are observed, which depend on the type of excitation. Instruments) grating 1800 and ANDOR IDUS CCD (DU420-OE respectively them spectral of our","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69615863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/4/201/2020
M. Kostyrko, I. Orykhivskyi, I. Skab, R. Vlokh
. We develop a new approach for determining some of elasto-optic coefficients ( p ij with i = 1…6 and j = 4, 5) basing on Dixon–Cohen method and acousto-optic diffraction at circularly polarized acoustic waves. Particular cases of crystals that belong to trigonal system and some symmetry groups of tetragonal and hexagonal systems are analyzed. We find that the effective elasto-optic coefficients are different for the alternative cases of diffractions at either right- or left-handed circularly polarized acoustic waves that propagate along Z axis in crystals. One can determine in this way the coefficients p 44 and p 45 at the anisotropic diffraction in the crystals belonging to point symmetry groups 4, 4/m, 4 , 6, 6/m and 6 . For the crystals belonging to symmetry groups 32, 3m and 3m , it is possible to determine the coefficients p 14 and p 44 respectively at the isotropic and anisotropic diffractions. Finally, for the crystals described by the groups 3 and 3 , one can determine separately the four coefficients p 44 , p 45 , p 25 and p 14 following from the anisotropic-diffraction data and the two coefficients p 14 and p 25 following from the isotropic-diffraction data.
{"title":"Peculiarities of acousto-optic diffraction at circularly polarized acoustic waves. Determination of elasto-optic coefficients coupled with shear waves. Errata","authors":"M. Kostyrko, I. Orykhivskyi, I. Skab, R. Vlokh","doi":"10.3116/16091833/21/4/201/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/4/201/2020","url":null,"abstract":". We develop a new approach for determining some of elasto-optic coefficients ( p ij with i = 1…6 and j = 4, 5) basing on Dixon–Cohen method and acousto-optic diffraction at circularly polarized acoustic waves. Particular cases of crystals that belong to trigonal system and some symmetry groups of tetragonal and hexagonal systems are analyzed. We find that the effective elasto-optic coefficients are different for the alternative cases of diffractions at either right- or left-handed circularly polarized acoustic waves that propagate along Z axis in crystals. One can determine in this way the coefficients p 44 and p 45 at the anisotropic diffraction in the crystals belonging to point symmetry groups 4, 4/m, 4 , 6, 6/m and 6 . For the crystals belonging to symmetry groups 32, 3m and 3m , it is possible to determine the coefficients p 14 and p 44 respectively at the isotropic and anisotropic diffractions. Finally, for the crystals described by the groups 3 and 3 , one can determine separately the four coefficients p 44 , p 45 , p 25 and p 14 following from the anisotropic-diffraction data and the two coefficients p 14 and p 25 following from the isotropic-diffraction data.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"23 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/4/207/2020
S. Ašmontas, L. Fedorenko, V. Vlasiuk, T. Gorbanyuk, V. Kostylyov, V. Lytovchenko, J. Gradauskas, A. Sužiedėlis, E. Sirmulis, O. Žalys, O. Masalskyi
. The surface of a silicon solar cell is modified to improve its photovoltaic characteristics. Nanostructured porous silicon layer is formed on a front n + -type surface of a p–n junction by means of electrochemical etching accompanied by illumination with a high-power light-emitting diode operating at the wavelength of 365 nm. Addition of the porous layer results in considerable increase in the capacitive photovoltage across the p–n junction. This increase is shown to be stipulated by reduced photonic losses due to anti-reflection coating effect of the porous layer, as well as by decreasing adverse effect of hot carriers on the photovoltage. Broadening of the spectrum of capacitive photovoltage towards the short-wavelength region was observed. This finding is associated with the graded-gap character of the porous layer and photovoltage formation across it as well as with increased absorption of high-energy photons in the porous layer and resulting weaker heating of free carriers.
{"title":"Suppression of hot carriers by nanoporous silicon for improved operation of a solar cell","authors":"S. Ašmontas, L. Fedorenko, V. Vlasiuk, T. Gorbanyuk, V. Kostylyov, V. Lytovchenko, J. Gradauskas, A. Sužiedėlis, E. Sirmulis, O. Žalys, O. Masalskyi","doi":"10.3116/16091833/21/4/207/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/4/207/2020","url":null,"abstract":". The surface of a silicon solar cell is modified to improve its photovoltaic characteristics. Nanostructured porous silicon layer is formed on a front n + -type surface of a p–n junction by means of electrochemical etching accompanied by illumination with a high-power light-emitting diode operating at the wavelength of 365 nm. Addition of the porous layer results in considerable increase in the capacitive photovoltage across the p–n junction. This increase is shown to be stipulated by reduced photonic losses due to anti-reflection coating effect of the porous layer, as well as by decreasing adverse effect of hot carriers on the photovoltage. Broadening of the spectrum of capacitive photovoltage towards the short-wavelength region was observed. This finding is associated with the graded-gap character of the porous layer and photovoltage formation across it as well as with increased absorption of high-energy photons in the porous layer and resulting weaker heating of free carriers.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.3116/16091833/21/4/170/2020
I. Dupliak, Yuchen Liang, Guozhu Yan, Fenping Li, K. Ivaniuk, Xiaogang Li
We create a high-precision surface microstructure at the surfaces of SAE 304 stainless steel plates, using picosecond-laser pulses with high repetition rates. The surfaces acquire cross-groove patterns due to a line-by-line laser ablation technology. The wettability of the microstructured metal surface is studied. The microstructured surface provides a superhydrophobicity with good anticorrosion and antibacterial properties, which can extend significantly the scope of applications of the underlying material.
{"title":"Picosecond-laser processing of stainless steel for fabricating superhydrophobic surfaces","authors":"I. Dupliak, Yuchen Liang, Guozhu Yan, Fenping Li, K. Ivaniuk, Xiaogang Li","doi":"10.3116/16091833/21/4/170/2020","DOIUrl":"https://doi.org/10.3116/16091833/21/4/170/2020","url":null,"abstract":"We create a high-precision surface microstructure at the surfaces of SAE 304 stainless steel plates, using picosecond-laser pulses with high repetition rates. The surfaces acquire cross-groove patterns due to a line-by-line laser ablation technology. The wettability of the microstructured metal surface is studied. The microstructured surface provides a superhydrophobicity with good anticorrosion and antibacterial properties, which can extend significantly the scope of applications of the underlying material.","PeriodicalId":23397,"journal":{"name":"Ukrainian Journal of Physical Optics","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69616594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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