Regensburg 2022 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.42: Poster

Wednesday, September 7, 2022, 18:00–20:00, P2

Graphitic Carbon Nitride/Semiconductor Quantum Dots 2D/0D Heterostructures — •Thuy Linh Nguyen Thi, Oleksandr Selyshchev, and Dietrich R.T. Zahn — Semiconductor Physics, TU Chemnitz, Chemnitz D-09107, Germany

The 2D semiconductor graphitic carbon nitride (g-C3N4) is of great interest due to its photocatalytic properties and potential application in optoelectronic devices. However, a relatively large bandgap of 2.7 eV [1] requires its additional sensibilization to extend the photosensitivity to entire visible range. Here, we investigate heterostructures of n-type g-C3N4 and p-type semiconductor quantum dots (QDs), e.g. AgInS2. The single-layered g-C3N4 flakes exfoliated from bulk material using tetraethylammonium hydroxide (TEA-OH) ligands [1] and AgInS2 QDs with a size of ~3.5 nm [2] were used in aqueous solutions. X-ray Diffraction (XRD) indicates the intercalation of TEA-OH ligands between the flakes of g-C3N4. The thickness of the carbon nitride flakes of 0.3 +/- 0.1 nm, corresponding to a monolayer, and lateral sizes in the range of 35 - 55 nm are confirmed by Atomic Force Microscopy (AFM). Photoluminescence (PL) quenching of both g-C3N4 and QDs indicates an electronic interaction. A model photodetector device based on a thin film of a g-C3N4 and QD mixture, a TiO2 transport layer, indium-tin-oxide and gold electrodes was utilized for investigating the photoconductivity.

[1] O. Stroyuk et al., Phys. Status Solidi B, 2018, 256, 2, 1800279.

[2] A. Raevskaya et al., J. Phys. Chem. C, 2017, 121,16, 9032.