Pure and yttrium (Y) doped ZnO samples were fabricated on micro slide glasses and p-Si wafers for device application via a simple and cheap sol–gel route using a spin coater. The characterization results of XRD, SEM and UV/VIS spectrophotometer revealed the films to have nano-sized ZnO hexagonal wurtzite structures with (002) preferential orientation and optical band gap values depending on Y doping ratio. The optical band of 3.285eV for pure ZnO initially increased to 3.305eV, 3.332eV and 3.341eV for 1at.%, 2at.% and 3at.% Y incorporated ZnO films and then decreased to 3.271eV and 3.258eV for 5at.% and 7at.% Y contents. The electrical features of Al/ZnO:Y/p-Si/Al heterojunction structures were tested by I–V measurements. The heterojunction structures showed a rectifying behavior under dark condition. The Φb and n values for the devices were identified by using I–V measurements. It was observed that the rectification ratio value of 3×104 calculated at +3.0V for Al/ZnO:Y/p-Si (5at.% Y doped ZnO) heterojunction structure was higher than most of n-ZnO/p-Si heterojunction devices reported in the literature.