Thermal effects on the Raman phonon of few-layer phosphorene
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583 (Singapore)
Two-dimensional phosphorene is a promising channel material for next generation transistor applications due to its superior carrier transport property. Here, we report the influence of thermal effects on the Raman phonon of few-layer phosphorene formed on hafnium-dioxide (HfO{sub 2}) high-k dielectric. When annealed at elevated temperatures (up to 200 °C), the phosphorene film was found to exhibit a blue shift in both the out-of-plane (A{sup 1}{sub g}) and in-plane (B{sub 2g} and A{sup 2}{sub g}) phonon modes as a result of compressive strain effect. This is attributed to the out-diffusion of hafnium (Hf) atoms from the underlying HfO{sub 2} dielectric, which compresses the phosphorene in both the zigzag and armchair directions. With a further increase in thermal energy beyond 250 °C, strain relaxation within phosphorene eventually took place. When this happens, the phosphorene was unable to retain its intrinsic crystallinity prior to annealing, as evident from the broadening of full-width at half maximum of the Raman phonon. These results provide an important insight into the impact of thermal effects on the structural integrity of phosphorene when integrated with high-k gate dielectric.
- OSTI ID:
- 22499225
- Journal Information:
- APL Materials, Vol. 3, Issue 12; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2166-532X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ultra‐Narrow Phosphorene Nanoribbons Produced by Facile Electrochemical Process
Direct Observation of Symmetry-Dependent Electron–Phonon Coupling in Black Phosphorus