Physical and electrical properties of Al/Nb2O5 thin film Schottky diode for UV-A applications

Abstract

Nb2O5 thin films were deposited through sol-gel technique and then the films were annealed at temperature 300, 400, 500 and 600°C. The effect of annealing temperatures on the physical properties of the films was analyzed by several characterization techniques. Secondary ion mass spectroscopy analysis results indicated that uniform Nb and O distribution have formed throughout depth of the films deposited on substrates. The Atomic Force Microscope results observed that the increased temperature has resulted in increasing the surface roughness from 1.07 to 4.58 nm. The energy band gap (3.67–3.51 eV) was determined to be decrease with increase the annealing temperature. Therefore, considering the results of the both as-deposited at 150 ˚C and annealed films, it is clearly seen that as-deposited at 150 ˚C film has most uniform depth, a homogeneous surface and the highest optical band gap (at UV-A region). Therefore, the Al/Nb2O5 Schottky diode was fabricated based on the as-deposited film. The current-voltage (I-V) characteristics of the diode were measured at room temperature and detail discussed. It has been observed that the diode has exhibited good rectifying behavior. The obtained experimental results showed that the as deposited Nb2O5 thin film can be used in UV-A electro-optical applications.