Regensburg 2019 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 48: Two-dimensional Materials IV (joint session HL/CPP)

HL 48.5: Talk

Friday, April 5, 2019, 10:30–10:45, H36

Nanoscale Mapping of Charge Transfer at SnS/MoS₂ 2D-2D p-n Junctions Created via Low-Temperature Epitaxy — •Alex Henning^{1, 2}, Jack N. Olding^1,3, Michael J. Moody¹, Jason Dong¹, Emily A. Weiss³, and Lincoln J. Lauhon¹ — ¹Department of Materials Science and Engineering, Northwestern University, USA — ²Walter Schottky Institute and Physics Department, Technische Universität München — ³Department of Chemistry, Northwestern University, USA

Many novel two-dimensional (2D) van der Waals (vdW) heterostructures with intriguing properties for optical and electronic applications have been created by mechanical exfoliation and stacking. The ability to directly grow vdW heterostructures over large areas would create new opportunities for large-scale integration. Here, p-type tin sulfide (SnS) is grown on n-type molybdenum disulfide (MoS₂) in an atomic layer deposition (ALD) reactor at low temperatures (180 ^∘C) to form vertical p-n 2D-2D heterojunctions (HJs). X-ray diffraction and electron backscatter diffraction establish an axiotaxial relationship between the two crystals. Kelvin probe force microscopy (KPFM) combined with a tunable illumination source is used to characterize the topography, potential landscape and photoresponse of the MoS₂/SnS HJs with a lateral resolution < 50 nm. The gained structural and electronic properties were used to optimize the parameters for the growth of electronically active SnS of controlled thickness. The built-in potential difference of 0.9 eV, measured between MoS₂ and SnS, is significantly larger than those previously reported for 2D HJs.