ESR study of heavily doped GaAs:Er grown by organometallic vapor phase epitaxy

Abstract

As the photo luminescence (PL) spectra of rare-earth doped III-V semiconductors are sharp and temperature-stable, a possibility to produce temperature-stable optical devices with rareearth doped III-V semiconductors has attracted much interest. X-band ESR measurements of heavily doped GaAs:Er, whose Er concentration was1.7X1020 cm-3 grown without additional O2 flow by organometallic vapor phase epitaxy (sample II), have been performed at 3.5K. Although an isotropic ESR signal was observed around g=6 in the GaAs:Er sample whose Er concentration was 3.6x1018 cm-3 grown with additional O2 flow by OMVPE (sample I), we did not observe an isotropic ESR signal around g=6 in sample II. It suggests that Er centers at the tetrahedral sites decreased in sample II. Several ESR signals with anisotropic g-values, which are different from those in sample I, were also observed in sample II, suggesting the formation of new Er centers with oxygen in sample II. The origin of these ESR signals is discussed in connection with PL results.