Atomic layer deposition-enabled single layer of tungsten trioxide across a large area

• Published in: Applied materials today Vol. 6; pp. 44 - 53
• Main Authors: Zhuiykov, Serge, Hyde, Lachlan, Hai, Zhenyin, Akbari, Mohammad Karbalaei, Kats, Eugene, Detavernier, Christophe, Xue, Chenyang, Xu, Hongyan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2017
• Subjects: Atomic layer deposition (ALD); Monolayer; Two-dimensional semiconductors; WO3; Monolayer; WO3; Atomic layer deposition (ALD); Two-dimensional semiconductors
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2016.12.004

[Display omitted] •Single layer of WO3 0.7±0.07nm was synthesized on a large scale by ALD technique.•(tBuN)2W(NMe2)2 as tungsten precursor and H2O as oxygen precursor were used.•ALD deposition at 350°C yields pure, stoichiometric single-layered WO3 films.•The created ALD recipe allows any number of atomic WO3 layers to be developed.•Response time of ∼1.0ms was recorder for photodetector based on monolayer WO3. Reduction from multi-layer to one fundamental layer thickness represents a variety of exotic properties and distinctive applications of such two-dimensional (2D) semiconductor as tungsten trioxide (WO3). This transition without damaging single layer on a large spatial resolution remained elusive until the atomic layer deposition (ALD) technique was utilized. Here we report for the first time the ALD-enabled atomic-layer-precision development of a single layer WO3 with thickness of 0.7±0.07nm across a large area by using (tBuN)2W(NMe2)2 as tungsten precursor and H2O as oxygen precursor, without affecting the underlying SiO2/Si substrate. Versatility of ALD is in tuning recipe in order to achieve the complete WO3 with desired number of WO3 layers including monolayer. Governed by self-limiting surface reactions, the ALD-enabled approach is versatile, scalable and applicable for a broader range of 2D semiconductors and various device applications. Photodetector based on monolayer WO3 exhibited extremely ultra-fast photo-response of ∼1.0ms.