Intentional ρ-type doping by carbon in metalorganic MBE of GaAs
We report on the intentional ρ-type doping of GaAs layers grown in an UHV system from molecular beams of arsine (AsH3) and mixtures of frimethyl gallium (TMG) and friethyl gallium (TEG). The entire doping range between 1014 cm-3 (growth from pure TEG) and 1020 cm-3 (growth from pure TMG) can be covered by using mixtures of TMG and TEG. As revealed by SIMS and photoluminescence (PL) carbon is the dominant acceptor in the layers. Comparison of the Hall mobility and of the PL spectra shows that the quality of our films equals that of the best LPE and MBE grown ρ-type GaAs layers.