Molten calcium-magnesium-alumina-silicate(CMAS)is easy to wet and penetrates into thermal barrier coatings(TBCs),causing coating corrosion and premature failure.The application of a protective layer on the TBC surface...Molten calcium-magnesium-alumina-silicate(CMAS)is easy to wet and penetrates into thermal barrier coatings(TBCs),causing coating corrosion and premature failure.The application of a protective layer on the TBC surface is considered a useful method to alleviate CMAS attack.In this study,a bilayer-structured apatite layer was developed,on which molten CMAS has low wettability.It had an acicular upper layer and a compact lower layer,which was constructed by pre-reacting GdPO4 with CMAS powders through precise regulation of the pre-reaction temperature,time,and CMAS concentration.The microstructure integrity of the bilayer-structured apatite layer remained intact after heat treatment at 1250℃ for 50 h,and the layer did not crack after 100 thermal cycles.When exposed to CMAS at 1250℃ for 20 h,the layer retained an intact structure and still functioned to prevent CMAS penetration.At 1250℃ for 30 min,the CMAS contact angle on the bilayer-structured apatite layer was 17.4°,which was three times greater than that on Gd2Zr2O7,which is another promising CMAS-resistant TBC material.Hence,the bilayer-structured apatite layer is quite attractive for addressing the CMAS issue of TBCs.展开更多
Suitable bandgap,high solar-blind light sensitivity,and high stability against harsh environments make Ga_(2)O_(3) a promising candidate in the application of solar-blind photodetectors.However,Ga_(2)O_(3) photodetect...Suitable bandgap,high solar-blind light sensitivity,and high stability against harsh environments make Ga_(2)O_(3) a promising candidate in the application of solar-blind photodetectors.However,Ga_(2)O_(3) photodetectors,particularly those dominated by the photoconductive effect,inevitably face a trade-off between photoresponsivity and response speed.Common methods to mitigate this trade-off usually improve one aspect with the compromise of another.In this work,bilayer-structure Ga_(2)O_(3) films are adopted for solar-blind photodetectors to alleviate the trade-off of photoresponsivity and response speed.The performance improvement effect of the bilayer-structure device is credited to its favorable modulation of carrier redistribution between two layers and extraction accessibility by the electrode.Through further optimization of film crystallinity by annealing,the bilayer-structure device acquires improved photoresponse performance,including a low dark current of 1.16 pA,a high photo to dark current ratio of 3.49×^(5),a high R of 236.10 A W^(–1),a high rejection ratio(R_(254nm)/R_(365nm))of 1.98×10^(5),and a fast decay speed of 50 ms.Such excellent comprehensive performance ranks it into the top level among similar Ga_(2)O_(3) photodetectors dominated by the photoconductive effect.This work provides a universal and facile design to mitigate the trade-off between photoresponsivity and response speed of Ga_(2)O_(3) solar-blind photodetectors.展开更多
基金the Innovation Project(No.D925BCD)the National Natural Science Foundation of China(Nos.52471087 and 52272070)the National Science and Technology Major Project(No.J2022-VI0009-0040).
文摘Molten calcium-magnesium-alumina-silicate(CMAS)is easy to wet and penetrates into thermal barrier coatings(TBCs),causing coating corrosion and premature failure.The application of a protective layer on the TBC surface is considered a useful method to alleviate CMAS attack.In this study,a bilayer-structured apatite layer was developed,on which molten CMAS has low wettability.It had an acicular upper layer and a compact lower layer,which was constructed by pre-reacting GdPO4 with CMAS powders through precise regulation of the pre-reaction temperature,time,and CMAS concentration.The microstructure integrity of the bilayer-structured apatite layer remained intact after heat treatment at 1250℃ for 50 h,and the layer did not crack after 100 thermal cycles.When exposed to CMAS at 1250℃ for 20 h,the layer retained an intact structure and still functioned to prevent CMAS penetration.At 1250℃ for 30 min,the CMAS contact angle on the bilayer-structured apatite layer was 17.4°,which was three times greater than that on Gd2Zr2O7,which is another promising CMAS-resistant TBC material.Hence,the bilayer-structured apatite layer is quite attractive for addressing the CMAS issue of TBCs.
基金National Key Research and Development Program of China Stem Cell and Translational Research,Grant/Award Numbers:2023YFB3610200,2024YFA120880,2024YFB3212200National Natural Science Foundation of China,Grant/Award Numbers:62474169,61925110,U20A20207,62304215Funding support from University of Science and Technology of China(USTC),Grant/Award Numbers:WK2100000025,KY2190000003,KY2190000006,YD2100002009。
文摘Suitable bandgap,high solar-blind light sensitivity,and high stability against harsh environments make Ga_(2)O_(3) a promising candidate in the application of solar-blind photodetectors.However,Ga_(2)O_(3) photodetectors,particularly those dominated by the photoconductive effect,inevitably face a trade-off between photoresponsivity and response speed.Common methods to mitigate this trade-off usually improve one aspect with the compromise of another.In this work,bilayer-structure Ga_(2)O_(3) films are adopted for solar-blind photodetectors to alleviate the trade-off of photoresponsivity and response speed.The performance improvement effect of the bilayer-structure device is credited to its favorable modulation of carrier redistribution between two layers and extraction accessibility by the electrode.Through further optimization of film crystallinity by annealing,the bilayer-structure device acquires improved photoresponse performance,including a low dark current of 1.16 pA,a high photo to dark current ratio of 3.49×^(5),a high R of 236.10 A W^(–1),a high rejection ratio(R_(254nm)/R_(365nm))of 1.98×10^(5),and a fast decay speed of 50 ms.Such excellent comprehensive performance ranks it into the top level among similar Ga_(2)O_(3) photodetectors dominated by the photoconductive effect.This work provides a universal and facile design to mitigate the trade-off between photoresponsivity and response speed of Ga_(2)O_(3) solar-blind photodetectors.
