the absorption for ion implanted defected si is much larger than that for crystal si over much of the visible and near infrared wavelength regions in particular wesch and gotz department of physics university of jena 34 influence of ion implantation on the optical properties of silicon 34 have shown that the absorption at 1 2 u03bcm saturates at a value of u02dc 4000 cm 1 near the amorphization dose they attribute the increased absorption to the formation of point defects in the vicinity of the amorphous clusters formed during implantation in addition to the absorption increase there is also an increase in the refractive index this will reflect some portion of the incident radiation back towards the surface and further increase the responsivity similarly zammit et al u zammit f gasparrini m marineill r pizzoferrato a agostini and f mercuri 34 ion dose effect in subgap absorption spectra of defects in ion implanted gaas and si 34 journal of applied physics v 70 no 11 pp 7060 7064 1 dec 1991 have shown a spectrally broad absorption in the sub bandgap region for ion implant damaged si independent of implant species and extending across all of the wavelengths presently of interest for.