Nb-doped ZnO transparent conducting films fabricated by pulsed laser deposition

Nb-doped ZnO thin films have been prepared on glass substrates by pulsed laser deposition (PLD). The effect of substrate temperature has been investigated from 100 to 500 °C by analyzing the structural, optical, and electrical properties. The Nb-doped ZnO films possessed a good crystallinity with a c-axis preferential orientation and a high transmittance (above 85%) in the visible region. The obtained film deposited at 350 °C exhibited the best electrical properties with the lowest room-temperature resistivity of around 5 × 10−4 Ω cm. Guided by x-ray photoemission spectroscopy analysis, NbZn3+ is believed to be the very possible donor in the Nb-doped ZnO films.