Using indium as catalyst for growth and simultaneously as doping source, ordered arrays of n-type ZnO single crystal nanorods have been perpendicularly grown on p-GaN/Al₂O₃ substrates with a vapor phase transport growth method. The low temperature photoluminescence measurements of the n-ZnO nanorods show dominant In-related neutral donor bound exciton emission in the ultraviolet region. Electrical transport measurements performed on single n-ZnO nanorods yield resistances of about 50–200  kOhm and a typical specific resistivity of 2.0×10⁻² Ohm cm. The resistivity is one order of magnitude reduced by introducing In compared to the nominally undoped ZnO nanorods.