Structural, nanomorphological and optical characteristics of self-assembled 2D-layered WS2-CdTe quantum dot heterostructure

Abstract

Abstract Self-assembled heterostructure of 2D-layered tungsten disulfide (WS2) with Cadmium telluride (CdTe) quantum dots is reported. CdTe quantum dots (8\xa0nm–10\xa0nm) were intercalated into 2D-layered WS2 which showed an approximate lateral length distribution of 1\xa0µm. X-ray photoelectron spectroscopic studies confirmed Cd (3d5/2, 3d3/2), Te (3d5/2, 3d3/2), W (4f7/2, 4f5/2) and S (2p3/2, 2p1/2) in the WS2-CdTe heterostructure which exhibited an optical absorption in the spectral range of 200\xa0nm–550\xa0nm. The dominant optical absorption around 250\xa0nm is attributed to the quantum size effects occurred on both WS2 and CdTe. A sharp photoluminescence emission at 600\xa0nm was further observed to be tunable with respect to concentration of CdTe quantum dots into the WS2 layers.