Edge assisted epitaxy of CsPbBr₃ nanoplates on Bi₂O₂Se nanosheets for enhanced photoresponse

【摘要】 Bi₂ O₂ Se has been proved to be a promising candidate for electronic and optoelectronic devices due to their unique physical properties.However,it is still a great challenge to construct the heterostructures with direct epitaxy of hetero semiconductor materials on Bi₂ O₂ Se nanosheets.Here,a two-step chemical vapor deposition（CVD） route was used to directly grow the CsPbBr₃ nanoplate-Bi₂ O₂ Se nanosheet hetero structures.The CsPbBr₃ nanoplates were selectively grown on the Bi₂ O₂ Se nanosheet along the edges,where the dangling bonds provide the nucleation sites.The epitaxial relationships between CsPbBr3 and Bi₂ O₂ Se were determined as [200]_{Bi2 O2 Se}‖[110]_CsPbBr3 and [110]_{Bi2 O2 Se}‖[200]_CsPbBr3by transmission electron microscopy characterization.The photoluminescence（PL） results reveal that the formation of heterostructures results in the remarkable PL quenching due to the type-Ⅰ band arrangement at CsPbBr₃/Bi₂ O₂ Se interface,which was confirmed by ultraviolet photoelectron spectroscopy（UPS） and Kelvin probe measurements,and makes the photogenerated carriers transfer from CsPbBr₃ to Bi₂ O₂ Se.Importantly,the photodetectors based on the heterostructures exhibit a 4-time increase in the responsivity compared to those based on the pristine Bi₂ O₂ Se sheets,and the fast rise and decay time in microsecond.These results indicate that the direct epitaxy of the CsPbBr₃ plates on the Bi₂ O₂ Se sheet may improve the optoelectronic performance of Bi₂ O₂ Se based devices.更多还原

【Abstract】 Bi₂ O₂ Se has been proved to be a promising candidate for electronic and optoelectronic devices due to their unique physical properties.However,it is still a great challenge to construct the heterostructures with direct epitaxy of hetero semiconductor materials on Bi₂ O₂ Se nanosheets.Here,a two-step chemical vapor deposition（CVD） route was used to directly grow the CsPbBr₃ nanoplate-Bi₂ O₂ Se nanosheet hetero structures.The CsPbBr₃ nanoplates were selectively grown on the Bi₂ O₂ Se nanosheet along the edges,where the dangling bonds provide the nucleation sites.The epitaxial relationships between CsPbBr3 and Bi₂ O₂ Se were determined as [200]_{Bi2 O2 Se}‖[110]_CsPbBr3 and [110]_{Bi2 O2 Se}‖[200]_CsPbBr3by transmission electron microscopy characterization.The photoluminescence（PL） results reveal that the formation of heterostructures results in the remarkable PL quenching due to the type-Ⅰ band arrangement at CsPbBr₃/Bi₂ O₂ Se interface,which was confirmed by ultraviolet photoelectron spectroscopy（UPS） and Kelvin probe measurements,and makes the photogenerated carriers transfer from CsPbBr₃ to Bi₂ O₂ Se.Importantly,the photodetectors based on the heterostructures exhibit a 4-time increase in the responsivity compared to those based on the pristine Bi₂ O₂ Se sheets,and the fast rise and decay time in microsecond.These results indicate that the direct epitaxy of the CsPbBr₃ plates on the Bi₂ O₂ Se sheet may improve the optoelectronic performance of Bi₂ O₂ Se based devices.更多还原