Subnano-scale selective etching and nano-scale pore array formation on inp [001] surfaces by a wet electrochemical process

Applicability of the wet electrochemical process to selective etching and nano-pore formation on n-InP (001) surfaces were investigated. The d.c. photo-anodic etching and the pulsed-avalanche etching in a IM HCl solution were found to be highly controllable and produce uniform and clean surfaces. In particular, the pulsed avalanche etching realized an extremely high etch depth controllability of 3×10^-5 nm/pulse. On the other hand, ⟨001⟩-oriented nanometer-sized straight pore arrays were successfully formed by the photo-anodization. The pore arrays exhibited intense and red-shifted PL emissions, which were probably due to a set of well defined surface states formed on the pore walls