Optical spectra and electron-Hole liquid in diamond

摘要

Optical absorption spectra in the spectral range from 200 nm to 15 mu m, Raman spectra in the wavenumber range of 100-3700 cm(-1), and photoluminescence spectra in the spectral range of 200-850 nm have been studied for five nominally "pure" diamond samples synthesized in different ways. The measurements have been carried out in the temperature range of 80-300 K. Photoluminescence was excited by the KrCl laser radiation at a wavelength of 222 nm with a pulse FWHM of 8 ns and a peak intensity on the sample surface of up to 13 MW/cm(2). It is found that, at absorption coefficients of diamond samples below 10 cm(-1) in the spectral range of 225-226 nm, their photoluminescence spectra exhibit a radiative recombination band of electron-hole liquid peaked at 240 nm.