We fabricated undoped and Cu doped TiO2 thin films by spin coating technique and employed the films as interfacial oxide layer between the Al and n-type Si to investigate the effect of temperature on the Al/TiO2/n-Si and Al/Cu:TiO2/n-Si devices. For that aim, the I–V measurements were performed in the range of 50 K–400 K by 50 K interval. The devices exhibited good rectifying behavior and thermal response in a wide range temperature. Ideality factor, barrier height and series resistance were calculated from I–V measurements for various temperatures by thermionic emission theory, Norde and Cheung methods and discussed in the details. The obtained results revealed that the device parameters are a strong function of the temperature. The interface states (Nss) were affected by the changing of the temperatures. The Al/TiO2/n-Si and Al/Cu:TiO2/n-Si devices can be performed for wide range temperatures in various technological applications.