Morphologies and nonlinear optical properties of fractal Ge nanocrystals embedded in Pd matrix

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

4 Scopus Citations
View graph of relations

Author(s)

  • Lijun Wang
  • Xiaojian Chen
  • Chen Chen
  • Yanyu Liu
  • Zhiwen Chen

Detail(s)

Original languageEnglish
Pages (from-to)21012-21017
Journal / PublicationJournal of Physical Chemistry C
Volume116
Issue number39
Publication statusPublished - 4 Oct 2012

Abstract

An integrated device or component for the semiconductor industry is highly desirable for versatile advanced applications. Group IV semiconductors such as germanium (Ge) and silicon (Si) are unique materials of widespread technological applications, particularly in the field of microelectronic devices and optoelectronic components. Herein, Pd/Ge bilayer films with interesting Ge clusters, which have noninteger dimensions and are called fractals, were successfully prepared by high-vacuum thermal evaporation techniques. It was found that Ge nanocrystals embedded in Pd matrix showed fascinating fractal morphologies with average size of fractal clusters at 680 nm and fractal dimension at 1.708 when the films were annealed at 350 °C for 30 min. The fractal clusters consisted of Ge nanocrystals with diameters ranging from 25 to 55 nm. Third-order optical nonlinearities of the annealed Pd/Ge bilayer films were investigated in detail by Z-scan techniques using a femtosecond laser. Experimental results indicated that the nonlinear absorption coefficient and refractive index of the fractal Ge nanocrystals embedded in Pd matrix were in the ranges from 3.4 to 4.3 × 10 -7 cm/W and from 4.2 to 5.0 × 10 -12 cm 2/W, respectively, when the input irradiance (I p) ranged from 0.58 to 1.65 GW/cm 2. This nonlinear optical material may be tailor-made for a large number of applications such as high-speed microelectronics and infrared optical micro/nanodevices. © 2012 American Chemical Society.

Citation Format(s)

Morphologies and nonlinear optical properties of fractal Ge nanocrystals embedded in Pd matrix. / Wang, Lijun; Chen, Xiaojian; Chen, Chen; Liu, Yanyu; Chen, Zhiwen; Shek, Chan-Hung; Wu, C. M. Lawrence; Lai, Joseph K.L.

In: Journal of Physical Chemistry C, Vol. 116, No. 39, 04.10.2012, p. 21012-21017.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review