Epitaxial growth of CsPbBr_(3)/PbS single-crystal film heterostructures for photodetection

Epitaxial high-crystallization film semiconductor heterostructures has been proved to be an effective method to prepare single-crystal films for different functional devices in modern microelectronics,electro-optics,and optoelectronics.With superior semiconducting properties,halide perovskite materials are rising as building blocks for heterostructures.Here,the conformal vapor phase epitaxy of CsPbBr3 on PbS single-crystal films is realized to form the CsPbBr3/PbS heterostructures via a two-step vapor deposition process.The structural characterization reveals that PbS substrates and the epilayer CsPbBr3 have clear relationships:CsPbBr3(110)//PbS(100),CsPbBr3[001]//PbS[001]and CsPbBr3[001]//PbS[010].The absorption and photoluminescence(PL)characteristics of CsPbBr3/PbS heterostructures show the broadband light absorption and efficient photogenerated carrier transfer.Photodetectors based on the heterostructures show superior photoresponsivity of 15 A/W,high detectivity of 2.65×10^(11) Jones,fast response speed of 96 ms and obvious rectification behavior.Our study offers a convenient method for establishing the high-quality CsPbBr3/PbS single-crystal film heterostructures and providing an effective way for their application in optoelectronic devices.

Vapor phase epitaxy of PbS single-crystal films on water-soluble substrates and application to photodetectors

Lead sulfide(PbS),a typical functional semiconductor material,has attracted serious attention due to its great potential in optoelectronics applications.However,controllable growth of PbS single-crystal film still remains a great challenge.Here,we report heteroepitaxial growth of large-scale highly crystalline PbS films on alkali salt(NaCl and KCl)substrates via chemical vapor deposition(CVD).Structural characterizations demonstrate that the as-grown PbS films exhibit an atomically sharp interface with the underlying substrates.The epitaxial relationships between the epilayers and substrates were determined to be PbS(100)//NaCl(100)or KCl(100),PbS[010]//NaCl[010]or KCl[010].Owing to the high solubility of alkali salt,the epitaxial PbS films can be rapidly released from the underlying substrates and transferred to other substrates of interest while maintaining good integrity and crystallinity,the process of which is particularly attractive in the fields of electronics and optoelectronics.Furthermore,photodetectors based on the transferred PbS films were fabricated,exhibiting a high photoresponsivity of 7.5 A/W,a detectivity of 1.44×10^(12)Jones,and a rapid response time of approximately 0.25 s.This work sheds light on the batch production,green transfer,and optoelectronic application of PbS films.