A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the ...A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900°C. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500°C had an apparent rate constant equal to 0.0075 min 1, which is superior to the performance of a commercial photocatalyst Degussa P25 Kapp = 0.0045 min 1 and of unmodified TiO2 （TP0500） Kapp = 0.0022 min 1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone （HQ）, benzoquinone （BQ） and （4CC） 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato （Lycopersicon esculentum） whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished展开更多
A monolithic integrated full-wave bridge rectifier consisted of horizontal Schottky-barrier diodes(SBD)is prepared based on 100 nm ultra-thin β-Ga_(2)O_(3)and demonstrated the solar-blind UV(SUV)light-modulated chara...A monolithic integrated full-wave bridge rectifier consisted of horizontal Schottky-barrier diodes(SBD)is prepared based on 100 nm ultra-thin β-Ga_(2)O_(3)and demonstrated the solar-blind UV(SUV)light-modulated characteristics.Under SUV light illumination,the rectifier has the excellent full-wave rectification characteristics for the AC input signals of 5,12,and 24 V with different frequencies.Further,experimental results confirmed the feasibility of continuously tuning the rectified output through SUV light-encoding.This work provides valuable insights for the development of optically programmable Ga_(2)O_(3)ACDC converters.展开更多
Recently,self-powered ultraviolet photodetectors(UV PDs)based on SnO_(2)have gained increasing interest due to its feature of working continuously without the need for external power sources.Nevertheless,the productio...Recently,self-powered ultraviolet photodetectors(UV PDs)based on SnO_(2)have gained increasing interest due to its feature of working continuously without the need for external power sources.Nevertheless,the production of the majority of these existing UV PDs necessitates additional manufacturing stages or intricate processes.In this work,we present a facile,cost-effective approach for the fabrication of a self-powered UV PD based on p-Si/n-SnO_(2)junction.The self-powered device was achieved simply by integrating a p-Si substrate with a n-type SnO_(2)microbelt,which was synthesized via the chemical vapor deposition(CVD)method.The high-quality feature,coupled with the belt-like shape of the SnO_(2)microbelt enables the favorable contact between the n-type SnO_(2)and p-type silicon.The built-in electric field created at the interface endows the self-powered performance of the device.The p-Si/n-SnO_(2)junction photodetector demonstrated a high responsivity(0.12 mA/W),high light/dark current ratio(>103),and rapid response speed at zero bias.This method offers a practical way to develop cost-effective and high-performance self-powered UV PDs.展开更多
A broad-spectrum UV photodetector with ultrahigh detectivity and rapid response speed has been achieved inβ-Ga_(2)O_(3)/GaN heterojunction,in which,theβ-Ga_(2)O_(3) is synthesized by substituting oxygen for nitrogen...A broad-spectrum UV photodetector with ultrahigh detectivity and rapid response speed has been achieved inβ-Ga_(2)O_(3)/GaN heterojunction,in which,theβ-Ga_(2)O_(3) is synthesized by substituting oxygen for nitrogen in the top layer of the GaN matrix at high temperature.The processes and mechanism of transforming GaN with varying crystal quality into β-Ga_(2)O_(3) at high temperatures were studied in detail.The newly formed oxide layer is a monoclinic β-Ga_(2)O_(3) with(01)preferred orientation.X-ray photoelectron spectroscopy(XPS)and atomic force microscope(AFM)measurements identified oxygen vacancies and surface flatness of β-Ga_(2)O_(3),respectively,which are closely related to the crystal quality of GaN.The oxygen vacancies and the root mean square of morphology roughness of β-Ga_(2)O_(3) decrease with the improvement of the precursor GaN crystal quality.The cross-section transmission electron microscope(TEM)measurements showed that a hexagonal phase GaN_(x)O_(3(1−x)/2)intermediate layer with a thickness of 5 nm exists at the interface region betweenβ-Ga_(2)O_(3) and hexagonal GaN.This indicates a molecular reconfiguration of the hexagonal system to a monoclinic system with oxygen substitution of nitrogen in GaN matrix.The metal-semiconductor-metal(MSM)planar structure device achieved an ultrahigh detection capability(Responsivity=2493.5 A/W,Detectivity>10^(16)Jones).The response time is in the order of milliseconds(τ_(r)=0.27 ms,τ_(d1)/τ_(d2)=0.33 ms/4.3 ms).A self-powered UV optoelectronic rapid response(τ_(r)=5µs,τ_(d1)/τ_(d2)=0.13 ms/2.3 ms)with the responsivity of 0.6 mA/W and the detectivity of 5.3×10^(11)Jones in the solar-blind wavelength region has been observed in the β-Ga_(2)O_(3)/GaN heterojunction without external bias.With a bias of−10 V loading,the response of the photodetector becomes a broad spectrum,covering the UVA-UVC wavelength range,and the photoresponsivity is up to 13.5 A/W.The detectivity reaches a high value of 2.6×10^(15)Jones.展开更多
文摘A series of phosphorus-modified titanium dioxide samples with varying P/Ti atomic ratio were conveniently prepared via a conventional solgel route. The effects of phosphorus content and calcination temperature on the crystalline structure, grain growth, surface area, and the photocatalytic activity of P-modified TiO2 were investigated. The XRD results showed that P species slow down the particle growth of anatase and increase the anatase-to-rutile phase transformation temperature to more than 900°C. Kinetic studies on the P-modified TiO2 to degraded 4-chlorophenol had found that the TP5500 prepared by adopting a P/Ti atomic ratio equal to 0.05 and calcined at 500°C had an apparent rate constant equal to 0.0075 min 1, which is superior to the performance of a commercial photocatalyst Degussa P25 Kapp = 0.0045 min 1 and of unmodified TiO2 （TP0500） Kapp = 0.0022 min 1. From HPLC analyses, various hydroxylated intermediates formed during oxidation had been identified, including hydroquinone （HQ）, benzoquinone （BQ） and （4CC） 4-chlorocatechol as main products. Phytotoxicity was assessed before and after irradiation against seed germination of tomato （Lycopersicon esculentum） whereas acute toxicity was assessed by using Folsomia candida as the test organism. Intermediates products were all less toxic than 4-chlorophenol and a significant removal of the overall toxicity was accomplished
基金supported by Natural Science Basic Research Program of Shaanxi Province of China(Grant No.2023JCYB574)National Natural Science Foundation of China(Grant No.62204203)。
文摘A monolithic integrated full-wave bridge rectifier consisted of horizontal Schottky-barrier diodes(SBD)is prepared based on 100 nm ultra-thin β-Ga_(2)O_(3)and demonstrated the solar-blind UV(SUV)light-modulated characteristics.Under SUV light illumination,the rectifier has the excellent full-wave rectification characteristics for the AC input signals of 5,12,and 24 V with different frequencies.Further,experimental results confirmed the feasibility of continuously tuning the rectified output through SUV light-encoding.This work provides valuable insights for the development of optically programmable Ga_(2)O_(3)ACDC converters.
基金support for this research was provided by the High-Level Scientific Research Cultivation Project at Hubei Minzu University,with the grant identifier PY22001the Guiding Projects from the Department of Education in Hubei Province,identified by the grant number B2018088.
文摘Recently,self-powered ultraviolet photodetectors(UV PDs)based on SnO_(2)have gained increasing interest due to its feature of working continuously without the need for external power sources.Nevertheless,the production of the majority of these existing UV PDs necessitates additional manufacturing stages or intricate processes.In this work,we present a facile,cost-effective approach for the fabrication of a self-powered UV PD based on p-Si/n-SnO_(2)junction.The self-powered device was achieved simply by integrating a p-Si substrate with a n-type SnO_(2)microbelt,which was synthesized via the chemical vapor deposition(CVD)method.The high-quality feature,coupled with the belt-like shape of the SnO_(2)microbelt enables the favorable contact between the n-type SnO_(2)and p-type silicon.The built-in electric field created at the interface endows the self-powered performance of the device.The p-Si/n-SnO_(2)junction photodetector demonstrated a high responsivity(0.12 mA/W),high light/dark current ratio(>103),and rapid response speed at zero bias.This method offers a practical way to develop cost-effective and high-performance self-powered UV PDs.
基金financially supported by National Key Technologies Research and Development Program of China(No.2019YFA0705202)National Natural Science Foundation of China(Nos.62274027,62404039)+3 种基金Open Research Fund of Songshan Lake Materials Laboratory(No.2023SLABFK03)Funding from Jilin Province(No.20220502002GH)Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(No.GZC20230416)Fundamental Research Funds for the Central Universities(No.2412024QD010).
文摘A broad-spectrum UV photodetector with ultrahigh detectivity and rapid response speed has been achieved inβ-Ga_(2)O_(3)/GaN heterojunction,in which,theβ-Ga_(2)O_(3) is synthesized by substituting oxygen for nitrogen in the top layer of the GaN matrix at high temperature.The processes and mechanism of transforming GaN with varying crystal quality into β-Ga_(2)O_(3) at high temperatures were studied in detail.The newly formed oxide layer is a monoclinic β-Ga_(2)O_(3) with(01)preferred orientation.X-ray photoelectron spectroscopy(XPS)and atomic force microscope(AFM)measurements identified oxygen vacancies and surface flatness of β-Ga_(2)O_(3),respectively,which are closely related to the crystal quality of GaN.The oxygen vacancies and the root mean square of morphology roughness of β-Ga_(2)O_(3) decrease with the improvement of the precursor GaN crystal quality.The cross-section transmission electron microscope(TEM)measurements showed that a hexagonal phase GaN_(x)O_(3(1−x)/2)intermediate layer with a thickness of 5 nm exists at the interface region betweenβ-Ga_(2)O_(3) and hexagonal GaN.This indicates a molecular reconfiguration of the hexagonal system to a monoclinic system with oxygen substitution of nitrogen in GaN matrix.The metal-semiconductor-metal(MSM)planar structure device achieved an ultrahigh detection capability(Responsivity=2493.5 A/W,Detectivity>10^(16)Jones).The response time is in the order of milliseconds(τ_(r)=0.27 ms,τ_(d1)/τ_(d2)=0.33 ms/4.3 ms).A self-powered UV optoelectronic rapid response(τ_(r)=5µs,τ_(d1)/τ_(d2)=0.13 ms/2.3 ms)with the responsivity of 0.6 mA/W and the detectivity of 5.3×10^(11)Jones in the solar-blind wavelength region has been observed in the β-Ga_(2)O_(3)/GaN heterojunction without external bias.With a bias of−10 V loading,the response of the photodetector becomes a broad spectrum,covering the UVA-UVC wavelength range,and the photoresponsivity is up to 13.5 A/W.The detectivity reaches a high value of 2.6×10^(15)Jones.
