Synthesis and nano-processing of ZnO nano-crystals for controlled laser action

K. Okazaki, T. Shimogaki, M. Higashihata, D. Nakamura, T. Okada

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Lasing characteristics of a single Zinc oxide (ZnO) nanosheet and a single ZnO nanowire were investigated by an ultraviolet light excitation. ZnO nanocrystals were synthesized by chemical vapor deposition (CVD) method, and those ZnO nanocrystals were excited by a third-harmonic Q-switched Nd: YAG laser beam (355 nm, 5 ns). The emission spectra from a single ZnO nanocrystal was collected by an objective lens with a magnification factor of 100 or 50, coupled with a spectrometer with a light fiber. The area observed by the spectrometer is about 10 μn in diameter, and therefore the emission spectra from a single ZnO nanocrystal can be observed. The emission spectra showed the obvious lasing characteristics having mode structure and a threshold for lasing. The lasing threshold power density of a ZnO nanosheet and a ZnO nanowire were measured to be about 60 kW/cm2 and 150 kW/cm2, respectively. ZnO nanosheet can be a superior laser medium due to the lower threshold for lasing compared to the threshold of the ZnO nanowire. However, since the lasing spectra had mode structure, a single-longitudinal mode lasing would be required for a practical application. The single longitudinal mode lasing can be realized by a nanomachining of a grating on the ZnO nanocrystal surface due to distributed bragg reflector (DBR) laser. The minimum DBR pitch was estimated to be about 81 nm, which can be machined by focused-ion beam (FIB) focused up to 7 nm at minimum, and therefore, we demonstrated the nanomachining on a single ZnO nanowire. However, the single-longitudinal mode lasing was not observed so far, and thus optimization of experimental conditions such as the DBR pitch, ion dose amount and increasing the number of repetition of DBR would be required.

Original languageEnglish
Title of host publicationNanowires and Nanotubes - Synthesis, Properties, Devices, and Energy Applications of One-Dimensional Materials
PublisherMaterials Research Society
Number of pages6
ISBN (Print)9781605114163
Publication statusPublished - 2012
Event2012 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 9 2012Apr 13 2012

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2012 MRS Spring Meeting
Country/TerritoryUnited States
CitySan Francisco, CA

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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