Raman study of the phonon halfwidths and the phonon—plasmon coupling in ZnO

✍ Scribed by B. H. Bairamov; A. Heinrich; G. Irmer; V. V. Toporov; E. Ziegler

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 500 KB
• Volume: 119
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2221190126

✦ Synopsis

Abstract

The LO‐phonon—plasmon coupling in n‐ZnO single crystals is investigated by Raman spectroscopy at room and liquid nitrogen temperatures. The energy shift and halfwidth broadening of the LO‐phonons relative to the uncoupled modes are analyzed to get the concentration and mobility of the charge carriers. These results are compared with those from electrical measurements. The uncoupled phonon modes are measured in high‐ohmic crystals in which the interaction with the charge carriers can be neglected. For the low energy E~2~ mode an extreme small halfwidth of 0.3 cm^−1^ is found. At 77 K with increasing intensity of the exciting continuous laser light (__h__ω = = 2.54 eV < E~g~ = 3.3 eV, P = 800 mW) nonequilibrium carriers are generated not connected with an increase of the lattice temperature.