NIR-CW-Laser annealing of room temperature sputtered ZnO:Al
Abstract
Transparent Conducting Oxides (TCOs) are widespread as transparent electrodes in thin film photovoltaics and electronics. Post deposition furnace annealing improves the electrical and optical properties of TCOs. Disadvantages of furnace annealing are large energy consumption and long processing time due to long-lasting heating ramps. ZnO:Al thin films (AZO) with a low electrical resistivity and high transparency are usually sputtered at substrate temperatures up to several hundred °C. In this study post deposition near infrared (NIR) continuous wave (CW) laser annealing of room-temperature deposited AZO thin films is investigated. The surface temperature is determined by infrared thermography. The averaged transmittance is increased by T300 - 1100 nm <= 7.2 % due to a lower absorptance at a constant reflectance. The resistivity is reduced to Rho=360 µ Omega cm, because of a higher electron mobility µ. These promising results show the potential of laser annealing for the replacement of furnace annealing in industrial applications.
