| AVS 62nd International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D+EM+MG+NS+SS+TF-ThA |
| Session: | Heterostructures of 2D Materials |
| Presenter: | Hui Zhu, UT-Dallas |
| Authors: | H. Zhu, UT-Dallas S. McDonnell, UT-Dallas X. Qin, UT-Dallas A. Azcatl, UT-Dallas L. Cheng, UT-Dallas R. Addou, UT-Dallas J. Kim, UT-Dallas P.D. Ye, Purdue University R.M. Wallace, UT-Dallas |
| Correspondent: | Click to Email |
Black phosphorus (“black-P”) is considered to be an appealing 2D material because of its novel properties and potential application in few-layer transistor structures.1,2,3 However, a clear challenge in the implementation of black-P is the strong hydrophilic4 and oxidation5 reactions during device processing and thereafter. Thus, efficient isolation layers are necessary for black-P to preserve its electronic properties. Al2O32 or HfO26 dielectric layers deposited by atomic layer deposition (ALD) have been used as isolation layers in recent black-P transistors. In this work, three different samples oxidized by ambient air were investigated to understand the interfacial chemistry, and nucleation of atomic layer deposited Al2O3 on black-P using in situ X-ray photoelectron spectroscopy (XPS). This work suggests that exposing a sample that is initially free of phosphorus oxide to the ALD precursors does not result in detectable oxidation. However, when the phosphorus oxide is formed on the surface prior to deposition, the black-P can react with both the surface adventitious oxygen contamination and the H2O precursor at the deposition temperature of 200 °C. As a result, the concentration of the phosphorus oxide increases after both annealing and the atomic layer deposition process. The nucleation rate of Al2O3 on black-P is correlated with the amount of oxygen on samples prior to the deposition. The growth of Al2O3 follows a “substrate inhibited growth” behavior where an incubation period is required. Ex situ atomic force microscopy is also used to investigate the deposited Al2O3 morphologies on black-P where the Al2O3 tends to form islands on the exfoliated black-P simples.
This work was supported in part by the SWAN Center, a SRC center sponsored by the Nanoelectronics Research Initiative and NIST, the Center for Low Energy Systems Technology (LEAST), one of the six SRC STARnet Centers, sponsored by MARCO and DARPA, and the US/Ireland R&D Partnership (UNITE) under the NSF award ECCS-1407765.
Reference:
1 L. Li, Y. Yu, G.J. Ye, Q. Ge, X. Ou, H. Wu, D. Feng, X.H. Chen, and Y. Zhang, Nat. Nanotech. 9, 372 (2014).
2 H. Liu, A.T. Neal, Z. Zhu, Z. Luo, X. Xu, D. Tománek, and P.D. Ye, ACS Nano 8, 4033 (2014).
3 F. Xia, H. Wang, and Y. Jia, Nat. Comm. 5, 4458 (2014).
4 J.D. Wood, S.A. Wells, D. Jariwala, K. Chen, E. Cho, V.K. Sangwan, X. Liu, L.J. Lauhon, T.J. Marks, and M.C. Hersam, Nano Lett. 14, 6964 (2014).
5 A. Favron, E. Gaufrès, F. Fossard, P.L. Lévesque, Anne-Laurence, Phaneuf-L’ Heureux, N.Y.-W. Tang, A. Loiseau, R. Leonelli, S. Francoeur, and R. Martel, arXiv:1408.0345 (2014).
6 N. Haratipour, M.C. Robbins, and S.J. Koester, arXiv:1409.8395 2 (2014).