Highly porous, individually separated, and vertically aligned rough silicon rods (r-SiRs) were formed via a modified electroless metal deposition (EMD) approach. Despite inheriting the length of crowded silicon nanowires (NWs) obtained by the conventionally adopted EMD method, the r-SiRs are distributed sparsely, subsequently forming an excellent field emitter substrate. The electron field emission (EFE) of carbon nanotubes (CNTs) grown on r-SiRs can be turned on at (E0)CNTs/r-SiRs ) 2.3 V/μm, yielding a high EFE current density, (Je)CNTs/r-SiR ) 3.7 mA/cm2 in an applied field of 5.1 V/μm. Additionally, a cactuslike structure consisting of zinc oxide NWs on r-SiRs can be turned on at 2.9 V/μm. The absence of a high-temperature or expensive photolithographic process makes r-SiRs a promising alternative as a silicon base field emitter substrate.