Deep levels in Yb-Al co-doped GaAs grown by liquid phase epitaxy

Deep-level transient spectroscopy (DLTS) and capacitance versus voltage measurements were used to study an influence of deep-level defects on electrical parameters of Yb-Al co-doped GaAs:Sn grown by liquid-phase epitaxy. DLTS spectra revealed the presence of several hole traps. Some of them were attributed to transition metals and native defects, respectively, which were commonly observed in as-grown material. It was found that increasing Yb caused a decrease in free carrier concentration. However, it was accompanied by an increase in the hole trap concentrations. On the other hand, adding Al resulted in a strong decrease in both the free carriers and the hole traps. The fact that deep levels may behave in this manner after adding Yb and Al into the Ga melt is an important factor to consider when interpreting changes in electrical parameters of the material.