Thickness-modulated in-plane Bi2O2Se homojunctions for ultrafast high-performance photodetectors<xref rid="cpb_28_12_128502fn1" ref-type="fn">*</xref><fn id="cpb_28_12_128502fn1"><label>*</label>Project supported by the National Natural Science Foundation of China (Grant No. 61705066), the Open Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China (Grant No. IPOC2018B004), and the National Key Research and Development Program, China (Grant No. 2016YFA0202401).</fn>

Thickness-modulated in-plane Bi₂O₂Se homojunctions for ultrafast high-performance photodetectors**

Project supported by the National Natural Science Foundation of China (Grant No. 61705066), the Open Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China (Grant No. IPOC2018B004), and the National Key Research and Development Program, China (Grant No. 2016YFA0202401).

Hong Cheng-Yun¹, Huang Gang-Feng¹, Yao Wen-Wen², Deng Jia-Jun², Liu Xiao-Long^{1, 3, †}

(a)–(c) Schematic illustration of Bi₂O₂Se homogeneous in-plane junction fabrication process with the mica substrate pre-treating, (d)–(f) Bi₂O₂Se in-plane junction formed by near-distance nucleation sites merging together, (g) optical microscopic image of Bi₂O₂Se IPJ constructed by two layers with different thicknesses, (h) Bi₂O₂Se IPJ consisting four layers, (i) Bi₂O₂Se IPJ formed by neighboring film merging together, where red dash lines represent the parallel crystal edges of thick Bi₂O₂Se film. All scale bars are 20 μm.