Epitaxial Growth of Optically Thick, Single Crystalline Silver Films for Plasmonics

Fei Cheng, Chien Ju Lee, Junho Choi, Chun Yuan Wang, Qiang Zhang, Hui Zhang, Shangjr Gwo, Wen-Hao Chang, Xiaoqin Li, Chih Kang Shih*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Single crystalline Ag films on dielectric substrates have received tremendous attention recently due to their technological potentials as low loss plasmonic materials. Two different growth approaches have been used to produce single crystalline Ag films previously. One approach is based on repetitive cycles of a two-step process (low temperature deposition followed by RT annealing) using molecular beam epitaxy (MBE), which is extremely time-consuming due to the need for repeat growth cycles. Another approach is based on rapid e-beam deposition which is capable of growing thick single crystalline Ag films (>300 nm) but lacks the precision in thickness control of thin epitaxial films. Here, we report a universal approach to grow atomically smooth epitaxial Ag films by eliminating the repetitive cycles used in the previous two-step MBE method while maintaining the precise thickness control from a few monolayers to the optically thick regime, thus overcoming the limitations of the two aforementioned methods. In addition, we develop an in situ growth of aluminum oxide as the capping layer to protect the epitaxial Ag films. The quality of the epitaxial Ag films was evaluated using a variety of techniques, and the superior optical performance of the films is demonstrated by measuring the propagation length of surface plasmon polaritons (∼80 μm at 632 nm) as well as their capability to support a plasmonic nanolaser in infrared incorporating an InGaAsP quantum well as the gain media.

Original languageEnglish
Pages (from-to)3189-3195
Number of pages7
JournalACS Applied Materials and Interfaces
Volume11
Issue number3
DOIs
StatePublished - 23 Jan 2019

Keywords

  • epitaxial growth
  • plasmonic lasing
  • propagation length
  • single crystalline silver film
  • surface plasmon polaritons

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