Soft photocurable nanoimprint lithography is used to transfer nanoscale features to GaAs substrates. Only ambient conditions without externally applied imprinting pressure are required during the imprinting step. The pattern which is transferred consists of a dense array of 100 nm features, either one-dimensional lines or two-dimensional holes. Both wet etching and dry etching are used to etch the GaAs for pattern transfer. Examination by atomic force microscopy and scanning electron microscopy confirms faithful pattern transfer; defects are few enough and patterned areas are large enough for optoelectronic device applications. (c) 2008 American Vacuum Society.