The photoluminescence and spectral photoconductivity of nanoporous GaN (NP-GaN) produced by electrochemical etching have been investigated. The NP-GaN showed large yellow luminescence attributed to the radiative recombination through surface states. It also displayed higher photocurrent and larger persistent photoconductivity compared to unetched n-GaN. Careful measurement of the below-band-edge photocurrent revealed an energy barrier of 304 meV for the recombination of photogenerated electrons and holes. This peculiar photoresponse could be explained with a space charge model in the nanoporous structure. The nanoporous GaN could be applied to the design of efficient solar cells and solar fuel devices. (C) 2013 Elsevier B.V. All rights reserved.