Abstract:
GeO2 thin film (TF) was fabricated by vapour deposition technique in a two zone horizontal quartz tube. Field
emission-scanning electron microscopy showed the formation of 200 nm TF on the Si (100) substrate. The X-ray
diffraction depicted the presence of the polycrystalline GeO2 TF. The UV–vis absorption spectrum showed humps
at 3.1 eV, 4.0 eV and 5.4 eV. The band anticrossing (BAC) model is modified using the Urbach equation to
understand the different transitions in the optical absorption spectrum. We have theoretically calculated the
relative refractive index (r.i.) (nr) of the GeO2 as 1.8. The temperature dependent current (I)–voltage (V)
characteristics and photocurrent of the Au/GeO2/p-Si Schottky device predicted the tunnelling of the carriers,
presence of oxygen defects at the junction. The device’s temporal response indicated good photosensitivity at all
temperatures and a significant increase in photocurrent was obtained as the temperature increased from 303 K to
403 K.
