Optical, electrical, and optoelectronic characterization of Ti-supersaturated gallium arsenide

Herein, a detailed investigation on the properties of supersaturated gallium arsenide (GaAs) using Ti${}^{+}$ implantation followed by nanosecond pulsed laser melting (PLM) is presented. The supersaturated samples are analyzed by means of electrical, optical, and optoelectronic characterization. The sheet resistance results obtained using van der Pauw configuration measurements do not show activation of the implanted Ti${}^{+}$ in semi-insulating GaAs after PLM. Absorptance measurements show a sub-bandgap absorption (up to 6.5% for $\lambda$ = 1000 nm) of the supersaturated GaAs:Ti and the just PLM-processed GaAs, with the same laser melting fluence used (0.50 J/cm${}^{-2}$). The origin of this sub-bandgap absorption is analyzed. Optoelectronic measurements show a similar sub-bandgap photo-response related to the absorption analyzed. The photo-response measured below the bandgap originates from point defects introduced by the PLM process. (© 2024 The Authors. physica status solidi (a) applications and materials science published by Wiley‐VCH GmbH)