Hollow Multi-Shelled Structures SnO₂ For The Application In Ultraviolet Photodetector

Ultraviolet light is significant concerned because it tremendous impact on people's daily life,industrial and agricultural production,herein,the fabrication of a UV photodetector with excellent photoelectric performance have attracted a broad attention.SnO2 has been reported as an ideal material for the detection of ultraviolet light due to its wide band gap accompanying with the transparency in visible spectral area.However,the responsivity and detectivity of reported SnO2 photodetectors are not satisfy due to the poor light utilization,which is a crucial part of photoelectric conversion process.Hollow multi-shelled structures(HoMSs)based materials have their natural advantages in light absorption because these multi shells can trap the light in their internal cavities.Circular nanospheres form a closed route to the incident light source and enable light to propagate along the spherical shells instead of directly cross over the spheres,which can improve the near-surface absorption efficiency thus improving the ability of light harness process,which is especially significant to a wide bandgap nanomaterial.Accordingly,a great option of UV sensitive materials SnO2 with a suitable structure HoMSs are hopeful to solve the weakness in responsivity and detectivity of traditional SnO2 photodetectors.Herein,the main research results of this paper can be divided into the following three aspects:(1)SnO2 HoMSs were synthesized by using the sequential templating approach with the template of alkali-treated carbonaceous microspheres(ATCMS),and the shell numbers of SnO2 HoMSs can be regulated by the adsorption of Sn4+ions concentrated in the center of the ATCMS.(2)The as-assembled SnO2 HoMSs were deposited on Si/SiO2 substrate by screen printing technique.The Cr/Au(200 nm/800 nm)electrodes were deposited on the surface of SnO2 HoMSs film by thermal evaporation.4S-SnO2 HoMSs photodetector exhibit the strongest light capture capability,a well photoelectric conversion ability accompanied by an R of 1.01 × 104 AW'1,EQE of 5.23 × 106%,and high D*of 3.83 ×1012 Jones which were enhanced by 35.3,38.4 and 33.9 times,respectively compared to those of SnO2 NPs device at 260 nm irradiation.(3)1S-,2S-,3S-,4S-SnO2 HoMSs and SnO2 NPs photodetectors were irradiated by different doses of gamma rays from 0 to 100 krad.With the increasing of irradiation dose,the photocurrent,R and D*of the photodetectors begin to attenuate.While the photoelectric parameters of HoMSs devices are all the higher than those of SnO2 NP one under all radiation doses.For example,when the radiation dose reaching to 100 krad,the R value of the SnO2 NPs device has decreased to 22.3 A/W,while it is still over 103 A/W for 4S-SnO2 HoMSs device.Here,we can conclude that the structure of HoMSs has shown its great advantages in the design of radiation-resistant and highly sensitive photodetectors.