Far-infrared absorption studies in MeV C⁺ and C₂⁺ implanted InSb (111) crystals

In this work, we briefly report on far-infrared absorption (FIR) studies on MeV C⁺ and C₂⁺ implanted InSb crystals in order to investigate the quality of the implanted layers and the basic difference in the C⁺ and C₂⁺ implantations. It is found from the FIR data that, in C₂⁺ implanted InSb samples, the transverse optical mode profile is broadened as compared to the samples implanted with C⁺ at the same energy/atoms and at a constant fluence. A detailed analysis shows that the conductivity in C₂⁺ irradiated specimen is enhanced compared to the C⁺ implantation. The results are attributed to the non-linear damage distribution due to C₂⁺ and the substitutional lattice site occupation of the implanted C atoms.