Growth of a uniform oxide film with a tunable thickness on two-dimensional transition metal dichalcogenides is of great importance for electronic and optoelectronic applications. Here we demonstrate homogeneous surface oxidation of atomically thin WSe2 with a self-limiting thickness from single- to trilayers. Exposure to ozone (O3) below 100 °C leads to the lateral growth of tungsten oxide selectively along selenium zigzag-edge orientations on WSe2. With further O3 exposure, the oxide regions coalesce and oxidation terminates leaving a uniform thickness oxide film on top of unoxidized WSe2. At higher temperatures, oxidation evolves in the layer-by-layer regime up to trilayers. The oxide films formed on WSe2 are nearly atomically flat. Using photoluminescence and Raman spectroscopy, we find that the underlying single-layer WSe2 is decoupled from the top oxide but hole-doped. Our findings offer a new strategy for creating atomically thin heterostructures of semiconductors and insulating oxides with potential for applications in electronic devices.
- Layered transition metal dichalcogenides
- tungsten diselenide
- Raman spectroscopy
- X-ray photoelectron spectroscopy
- ab initio calculations
Yamamoto, M., Dutta, S., Aikawa, S., Nakaharai, S., Wakabayashi, K., Fuhrer, M., Ueno, K., & Tsukagoshi, K. (2015). Self-limiting layer-by-layer oxidation of atomically thin WSe2. Nano Letters, 15(3), 2067-2073. https://doi.org/10.1021/nl5049753