Nano-porous silicon (NP-Si) and nano-inverted-pyramid silicon (NIP-Si) structures have been formed by Ag-catalyzed chemical etching without and with NaOH modification on solar-grade multi-crystalline silicon substrates, respectively. The influence of nano-structured morphology (NSM) and SiNx layer (SL) on effective reflectance (R-eff) has been investigated through measurement and simulation. For typical NP-Si and NIP-Si samples, the NSM alone can suppress R-eff of NP-Si sample to the lowest degree (5.87%), and the combination of NSM and SL is favorable to gain the lowest optical loss for NIP-Si sample (R-eff = 7.31%). Compared with NP-Si solar cell, the fabricated NIP-Si solar cells have hugely improved photovoltaic properties, resulting from reduced reflectance in visible and near-infrared wavelength, enhanced short-wavelength spectral responses and good diode parameters. Finally, an optimum design strategy of NSM and SL has been suggested to gain potentially better properties for nano-structured solar cells. (C) 2013 Elsevier Ltd. All rights reserved.