Detailed Examination of Relaxation Processes of Excitons in Photoluminescence Spectra of Cu_<b>2</b>O

Abstract

Variations of optical absorption and especially of photoluminescence spectra of Cu 2 O with photoexcitation wavelength and temperature have been for the first time investigated in details. We have newly observed that the relation of the increase and decrease with temperature in the integrated intensity is complementary with each other between the luminescence-band V Cu and the X O -Γ 12 - exciton luminescence over T =4.2–230 K, and the relative magnitudes of the intensity of the band V Cu and V O 2+ cross over each other at the vicinity of the energy level of exciton, λ∼610 nm. We recognize the evidences of the recombination processes of the excitons coupled with vacancies levels. These phenomena indicate universal natures even among the different quality of specimens. Thus, we request a consideration based on the many-body aspect.