Optoelectronic properties of nanoporous Ge layers investigated by surface photovoltage spectroscopy

• Nanoporous germanium layers obtained by Ge+ ion self-implant were investigated.
• The fundamental optical absorption energies of nanoporous Ge were measured.
• Au nanoparticles were embedded within the nanoporous Ge structure.
• Au nanoparticles caused the enhancement of the surface photovoltage.
• This nanoporous structure could be employed in future photovoltaic applications.

Optoelectronic properties of nanoporous Ge (np-Ge) have been investigated by Surface Photovoltage Spectroscopy. Electronic transitions in np-Ge have been compared with the ones obtained on crystalline and amorphous Ge, their dependence on ion implantation fluence and annealing treatment has been investigated. Np-Ge layers decorated with Au nanoparticles have been studied, and a significant photovoltage enhancement, probably related to light trapping effects, has been found. This result can be of major interest for future photovoltaic applications.

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