MOLECULAR-BEAM EPITAXIAL-GROWTH AND CHARACTERIZATION OF ERBIUM-DOPED GAAS AND ALGAAS

An exploratory study of the molecular-beam epitaxial growth and characterization of Er-doped GaAs and AlGaAs is described. Information regarding incorporation rate, diffusion, and surface riding of Er is obtained via secondary ion mass spectrometry and reflective electron diffraction measurements. Low temperature photoluminescence (PL) measurements near 1.54-mu-m show emission from multiple Er sites in AlGaAs:Er and GaAs:Er. Substrate temperature is found to affect PL spectra in a complicated manner. The dependence of Er-center PL intensity on Er concentration is very nonlinear and peaks at [Er] almost-equal-to 10(19) cm-3. GaAs:Er samples with [Er] = 6 x 10(18) cm-3 are p type with room temperature hole concentrations of 2-5 x 10(16) cm-3. Co-doping with Er and Si dramatically reduces electron concentration from that obtained with Si only, while the presence of Si reduces the Er-center PL intensity.