Study of optical transitions in an individual ZnO tetrapod using two-photon photoluminescence excitation spectrum

• Published in: Applied physics. B, Lasers and optics Vol. 97; no. 1; pp. 125 - 128
• Main Authors: Zhong, Y. C., Wong, K. S., Djurišić, A. B., Hsu, Y. F.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.09.2009; Springer
• Subjects: Engineering; Exact sciences and technology; Excitation; Excitation spectra; Frequency conversion ; harmonic generation, including high-order harmonic generation; Fundamental areas of phenomenology (including applications); Lasers; Nanocomposites; Nanostructure; Nonlinear optics; Optical Devices; Optical transition; Optics; Photoluminescence; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Zinc oxide; 42.65.-k; 78.47.Cd; 78.67.Bf; Second harmonic generation; Two photon excitation; Photoluminescence; Binary compounds; Zinc Oxides; Nanostructures; Pulsed lasers; Excitons; II-VI semiconductors; fs range; Excitation spectrum; Optical frequency conversion; Nonlinear optics
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-009-3625-6

Two-photon excited photoluminescence (PL) measurements have been carried out on an individual ZnO tetrapod at low temperature (8 K) using femtosecond laser pulses in the wavelength range of 714–850 nm. Simultaneously PL and second-harmonic generation were observed. The integrated PL intensity excitation spectrum at different two-photon excitation frequencies has eight peaks, which are in good correspondence to the exciton-phonon complexes L 1 b , L 1 a , and the free exciton lines B n =3 , A n =3 , B n =2 , A n =2 , B n =1 , and A n =1 seen in ZnO film. This technique can be used to measure the optical transitions in individual nanostructures, which is very difficult to achieve using the traditional transmission/reflection method.