The semiconductor nanowire (NW) technology has raised attention owing to its one-dimensional geometry as a solution for lattice mismatch in the fabricated heterostructures. Although, SiNWs have been investigated for various device technologies, there is no published work on the p-n junction formed by deposition of ZnSe thin film on these NW structures, in which this film layer has significant optical and electrical properties in optoelectronics applications. The aim of this study is determining the device properties of n-ZnSe/SiNW heterojunction and obtaining the enhancement in the device application of the NW structure on Si surface with comparing to planar surface. SiNW was produced by metal assisted etching method as a cost-efficient process, and the ZnSe film was deposited on SiNW and planar Si substrates by thermal evaporation of elemental sources. The optical band gap of the deposited ZnSe film was determined as 2.7eV which is in a good agreement with literature. The ideality factor and series resistance values of the ZnSe/SiNW and ZnSe/Si heterojunctions were calculated as 3.12, 461 , and 4.52, 7.26x103, respectively. As a result of utilizing SiNW structure, a spectacular improvement in terms of the physical parameters related to device properties was achieved.