Pressure Tuning of the Optical Properties of GaAs Nanowires

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• 作者：Ilaria Zardo ; Sara Yazji ; Carlo Marini ; Emanuele Uccelli ; Anna Fontcuberta i Morral ; Gerhard Abstreiter ; Paolo Postorino
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：April 24, 2012
• 年：2012
• 卷：6
• 期：4
• 页码：3284-3291
• 全文大小：502K
• 年卷期：v.6,no.4(April 24, 2012)
• ISSN：1936-086X

文摘

The tuning of the optical and electronic properties of semiconductor nanowires can be achieved by crystal phase engineering. Zinc-blende and diamond semiconductors exhibit pressure-induced structural transitions as well as a strong pressure dependence of the band gaps. When reduced to nanoscale dimensions, new phenomena may appear. We demonstrate the tuning of the optical properties of GaAs nanowires and the induction of a phase transition by applying an external pressure. The dependence of the E₀ gap on the applied pressure was measured, and a direct-to-indirect transition was found. Resonant Raman scattering was obtained by pressure tuning of the E₀ and the E₀ + 螖_SO gaps with respect to the excitation energy. The resonances of the longitudinal optical modes LO and 2LO indicate the presence of electron鈥損honon Fr枚hlich interactions. These measurements show for the first time a variation of ionicity in GaAs when in nanowire form. Furthermore, the dependence of the lattice constant on applied pressure was estimated. Finally, we found a clear indication of a structural transition above 16 GPa.

Keywords:

nanowires; optical properties; high pressure; Raman spectroscopy; resonant Raman