Synthesis of 2D Gallium Sulfide with Ultraviolet Emission by MOCVD – Publication by A4 (Gottfried), A5 (Volz), A14 (Volz) and B2 (Chatterjee) in Small

In a joint study of the projects A4, A5, A14 and B2, the two-dimensional growth of GaS on sapphire by MOCVD was successfully studied and the layers were characterized using a wide variety of techniques.

2D materials exhibit the potential to transform semiconductor technology. Their rich compositional and stacking varieties allow tailoring materials’ properties toward device applications. Monolayer to multilayer GaS, with its ultraviolet band gap, which can be tuned by varying the layer number, holds promise for solar‐blind photodiodes and light‐emitting diodes as applications.

In this cooperative study of different groups within the SFB 1083, the one‐step synthesis of 2D GaS is introduced via MOCVD (metal–organic chemical vapor deposition) on sapphire substrates. The pulsed‐mode deposition of industry‐standard precursors promotes 2D growth by inhibiting the vapor phase and on‐surface pre‐reactions. High resolution STEM imaging proves the ML nature of the GaS, but also shows a covalently bonded Ga adlayer on the sapphire, which plays an important role in mediating the epitaxial relationship of the GaS ML with respect to the sapphire substrate. The structural and chemical composition determined by electron microscopy related techniques are corroborated by XRR, XPS, Raman spectroscopy and PL and confirm a 2D nucleation of GaS on sapphire, which is an intricate balance between surface wetting, Ga droplet formation and strain-induced change of atomic spacing as well as van der Waals distances.

Growth model of the flow modulated GaS deposition.

The results highlight the adaptability of established growth facilities for producing atomically thin to multilayered 2D semiconductor materials, paving the way for practical applications.


O. Maßmeyer, R. Günkel, J. Glowatzki, P. Klement, B. Ojaghi Dogahe, S.R. Kachel, F. Gruber, M. Müller, M. Fey, J. Schörmann, J. Belz, A. Beyer, J.M. Gottfried, S. Chatterjee, K. Volz
Synthesis of 2D Gallium Sulfide with Ultraviolet Emission by MOCVD
Small (2024) 2402155 DOI:10.1002/smll.202402155


Prof. Dr. Kerstin Volz
Philipps-Universität Marburg
SFB 1083 project A5, A14, B13
Tel.: 06421 28-22297