S-doped and Al-doped GaSe crystals are promising materials for their applications in nonlinear frequency conversion devices. The optical and defect properties of pure, S-doped, and Al-doped GaSe crystals were studied ...S-doped and Al-doped GaSe crystals are promising materials for their applications in nonlinear frequency conversion devices. The optical and defect properties of pure, S-doped, and Al-doped GaSe crystals were studied by using photoluminescence（PL） and Fourier transform infrared spectroscopy（FT-IR）. The micro-topography of（0001） face of these samples was observed by using scanning electron microscope（SEM） to investigate the influence of the doped defects on the intralayer and interlayer chemical bondings. The doped S or Al atoms form the SSe^0 or AlGa^＋1） substitutional defects in the layer GaSe structure, and the positive center of AlGa-^＋1 could induce defect complexes. The incorporations of S and Al atoms can change the optical and mechanical properties of the GaSe crystal by influencing the chemical bonding of the layer structure. The study results may provide guidance for the crystal growth and further applications of S-doped and Al-doped GaSe crystals.展开更多
The electrical conductivity and Hall effect for T1GaSeS crystals have been investigated over a wide temperature range. The crystals we used are grown by a modified Bridgman technique and possess p-type conductivity. T...The electrical conductivity and Hall effect for T1GaSeS crystals have been investigated over a wide temperature range. The crystals we used are grown by a modified Bridgman technique and possess p-type conductivity. The energy gap has been found to be 1.63 eV, whereas the ionization energy is 0.25 eV. The variations of the Hall mobility as well as the carrier concentration with temperature have been investigated. The scattering mechanisms of the carder are checked over the whole investigated temperature range. Furthermore, the diffusion coefficient, relaxation time, and diffusion length of holes are estimated.展开更多
In this review,we introduce the current state of the art of the growth technology of pure,lightly doped,and heavily doped(solid solution)nonlinear gallium selenide(GaSe)crystals that are able to generate broadband emi...In this review,we introduce the current state of the art of the growth technology of pure,lightly doped,and heavily doped(solid solution)nonlinear gallium selenide(GaSe)crystals that are able to generate broadband emission from the near infrared(IR)(0.8 mm)through the mid-and far-IR(terahertz(THz))ranges and further into the millimeter wave(5.64 mm)range.For the first time,we show that appropriate doping is an efficient method controlling a range of the physical properties of GaSe crystals that are responsible for frequency conversion efficiency and exploitation parameters.After appropriate doping,uniform crystals grown by a modified technology with heat field rotation possess up to 3 times lower absorption coefficient in the main transparency window and THz range.Moreover,doping provides the following benefits:raises by up to 5 times the optical damage threshold;almost eliminates two-photon absorption;allows for dispersion control in the THz range independent of the mid-IR dispersion;and enables crystal processing in arbitrary directions due to the strengthened lattice.Finally,doped GaSe demonstrated better usefulness for processing compared with GaSe grown by the conventional technology and up to 15 times higher frequency conversion efficiency.展开更多
This paper describes syntheses and structure determination of four lanthanide complexes [Nd(2-Cl-4-FBA) 3 phen] 2 (1, 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate, phen = 1,10-phenanthroline), [Ln(2,5-DClBA) 3 phen] 2 (Ln =...This paper describes syntheses and structure determination of four lanthanide complexes [Nd(2-Cl-4-FBA) 3 phen] 2 (1, 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate, phen = 1,10-phenanthroline), [Ln(2,5-DClBA) 3 phen] 2 (Ln = Sm(2) and Tb(3), 2,5-DClBA = 2,5-dichlorobenzoate) and [Sm(2-Cl-4,5-DFBA) 3 (phen)(H 2 O)] 2 (4, (2-Cl-4,5-DFBA = 2-chloro-4,5-difluorobenzo- ate). The complexes were characterized by elemental analysis, infrared and ultraviolet spectra, and X-ray single-crystal diffraction. In the molecular structures of 1 4, two Ln 3+ ions are linked by four carboxyl groups, with two of them in a bridging bidentate mode and the other two in a bridging-chelating tridentate mode, forming four binuclear molecules. In addition, each Ln 3+ ion is also chelated to one phen molecule and one carboxyl group in the complexes, except each Sm 3+ ion in 4 which is bonded to one carboxyl group by unidentate mode and one H 2 O molecule. There are two different coordination polyhedrons for each Nd 3+ ion in the two similar molecular structures of 1 and they are a distorted monocapped square antiprismatic and a distorted tricapped triangular prism conformation, respectively. The coordination polyhedron for each Ln 3+ ion in 2 4 is a nine-coordinated distorted mono-capped square antiprismatic conformation. The complex 3 exhibits green luminescence under the radiation of UV light. The thermal decomposition behaviors of the complexes have been discussed by simultaneous TG/DSC-FTIR technique. The 3D surface graphs for the FTIR spectra of the evolved gases were recorded and the gaseous products were identified by the typical IR spectra obtained at different temperatures from the 3D surface graphs. Meanwhile, we discussed the nonisothermal kinetics of 1 4 by the integral isoconversional non-linear (NL-INT) method.展开更多
基金Project supported by Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.CXJJ-16M128)
文摘S-doped and Al-doped GaSe crystals are promising materials for their applications in nonlinear frequency conversion devices. The optical and defect properties of pure, S-doped, and Al-doped GaSe crystals were studied by using photoluminescence（PL） and Fourier transform infrared spectroscopy（FT-IR）. The micro-topography of（0001） face of these samples was observed by using scanning electron microscope（SEM） to investigate the influence of the doped defects on the intralayer and interlayer chemical bondings. The doped S or Al atoms form the SSe^0 or AlGa^＋1） substitutional defects in the layer GaSe structure, and the positive center of AlGa-^＋1 could induce defect complexes. The incorporations of S and Al atoms can change the optical and mechanical properties of the GaSe crystal by influencing the chemical bonding of the layer structure. The study results may provide guidance for the crystal growth and further applications of S-doped and Al-doped GaSe crystals.
文摘The electrical conductivity and Hall effect for T1GaSeS crystals have been investigated over a wide temperature range. The crystals we used are grown by a modified Bridgman technique and possess p-type conductivity. The energy gap has been found to be 1.63 eV, whereas the ionization energy is 0.25 eV. The variations of the Hall mobility as well as the carrier concentration with temperature have been investigated. The scattering mechanisms of the carder are checked over the whole investigated temperature range. Furthermore, the diffusion coefficient, relaxation time, and diffusion length of holes are estimated.
基金This work is supported in part by the Visiting Professor Program of State Key Laboratory of Laser Interaction with Matter of Changchun Institute of Optics,Fine Mechanics and Physics CAS,Changchun,China,the Open Fund by State Key Laboratory of Laser Interaction with Matter(No.SKLLIM1012)the RNF(Project No.15-19-10021,physical properties study),the Tomsk State University(8.1.51.2015)+1 种基金Tomsk Regional Common Use Center,with the support of the Russian Ministry of Education and Science(Agreement No.14.594.21.0001,code RFMEFI59414X0001,spectroscopic study)the Presidium SB RAS,Project VIII.80.2.4(optical properties study in THz range).
文摘In this review,we introduce the current state of the art of the growth technology of pure,lightly doped,and heavily doped(solid solution)nonlinear gallium selenide(GaSe)crystals that are able to generate broadband emission from the near infrared(IR)(0.8 mm)through the mid-and far-IR(terahertz(THz))ranges and further into the millimeter wave(5.64 mm)range.For the first time,we show that appropriate doping is an efficient method controlling a range of the physical properties of GaSe crystals that are responsible for frequency conversion efficiency and exploitation parameters.After appropriate doping,uniform crystals grown by a modified technology with heat field rotation possess up to 3 times lower absorption coefficient in the main transparency window and THz range.Moreover,doping provides the following benefits:raises by up to 5 times the optical damage threshold;almost eliminates two-photon absorption;allows for dispersion control in the THz range independent of the mid-IR dispersion;and enables crystal processing in arbitrary directions due to the strengthened lattice.Finally,doped GaSe demonstrated better usefulness for processing compared with GaSe grown by the conventional technology and up to 15 times higher frequency conversion efficiency.
基金supported by RFBR Project(No.10-02-01452-a)Presidium SB RAS under the Project VII.63.3.1 of VII.63.3 ProgJoin Proj.between Presidium SB RAS and Presidium NAS,Belarus No.10 of 2010
基金the National Natural Science Foundation of China (21073053,21073052 and 20773034)the Natural Science Foundation of Hebei Province (B2012205022)
文摘This paper describes syntheses and structure determination of four lanthanide complexes [Nd(2-Cl-4-FBA) 3 phen] 2 (1, 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate, phen = 1,10-phenanthroline), [Ln(2,5-DClBA) 3 phen] 2 (Ln = Sm(2) and Tb(3), 2,5-DClBA = 2,5-dichlorobenzoate) and [Sm(2-Cl-4,5-DFBA) 3 (phen)(H 2 O)] 2 (4, (2-Cl-4,5-DFBA = 2-chloro-4,5-difluorobenzo- ate). The complexes were characterized by elemental analysis, infrared and ultraviolet spectra, and X-ray single-crystal diffraction. In the molecular structures of 1 4, two Ln 3+ ions are linked by four carboxyl groups, with two of them in a bridging bidentate mode and the other two in a bridging-chelating tridentate mode, forming four binuclear molecules. In addition, each Ln 3+ ion is also chelated to one phen molecule and one carboxyl group in the complexes, except each Sm 3+ ion in 4 which is bonded to one carboxyl group by unidentate mode and one H 2 O molecule. There are two different coordination polyhedrons for each Nd 3+ ion in the two similar molecular structures of 1 and they are a distorted monocapped square antiprismatic and a distorted tricapped triangular prism conformation, respectively. The coordination polyhedron for each Ln 3+ ion in 2 4 is a nine-coordinated distorted mono-capped square antiprismatic conformation. The complex 3 exhibits green luminescence under the radiation of UV light. The thermal decomposition behaviors of the complexes have been discussed by simultaneous TG/DSC-FTIR technique. The 3D surface graphs for the FTIR spectra of the evolved gases were recorded and the gaseous products were identified by the typical IR spectra obtained at different temperatures from the 3D surface graphs. Meanwhile, we discussed the nonisothermal kinetics of 1 4 by the integral isoconversional non-linear (NL-INT) method.
