Novel Al/CoFe/p-Si and Al/NiFe/p-Si MS-type photodiode for sensing

CoFe and NiFe are used in the construction of Si-based metal-semiconductor-type photodiodes. Thin film layers are sputtered onto the<i>p</i>-Si surface where Al metal contacts are deposited using the thermal evaporation technique. Film characteristics of the layers are investigated with respect to the crystalline structure and surface morphology. Their electrical and optical properties are investigated using dark and illuminated current-voltage measurements. When these two diodes are compared, Al/NiFe/<i>p</i>-Si exhibits better rectification properties than Al/CoFe/<i>p</i>-Si diode. There is also a high barrier height where these values for both diodes increase with illumination. According to the current-voltage analysis, the existence of an interlayer causes a deviation in diode ideality. In addition, the response to bias voltage, the derivation of electrical parameters, and the light sensitivity of diodes are evaluated using current-voltage measurements under different illumination intensities and also transient photosensitive characteristics.