Exploring p type conductivity in ZnO thin films by In–N codoping for homo-junction devices

N monodoped and In–N codoped p type ZnO thin films were deposited on glass substrates by spray pyrolysis technique. XRD analysis revealed the monophasic polycrystalline characteristic and EDX spectra confirmed the better incorporation of N in ZnO matrix with In–N codoping. N monodoped film showed higher resistivity and hence cannot be useful as transparent conductor. In–N codoped films showed higher hole concentration and better mobility and are stable also. Further increase in In concentration resulted in decrease in mobility and hence resistivity increased. The optical characterization confirmed the films’ suitability as transparent conductor in various device applications. In–N codoping enhanced the optical energy gap due to Burstein–Moss effect and increase in band gap with increase in In concentration is attributed to the deterioration in crystallinity. The photoluminescence spectral analysis justified the efficacy of In in substituting N at oxygen sites as acceptors. The I–V characteristics of a diode structure fabricated with In–N codoped ZnO as p type layer and Al doped ZnO as n type layer showed the rectifying nature and confirmed the p type conductivity of In–N codoped ZnO thin film.