Reduced doping efficiency of aluminium in Al-doped ZnO film: role of excess aluminium and deposition rate
- PDF / 2,044,894 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 5 Downloads / 155 Views
Reduced doping efficiency of aluminium in Al‑doped ZnO film: role of excess aluminium and deposition rate Narendra Bandaru1 · Emila Panda1 Received: 26 March 2020 / Accepted: 5 June 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract This work addresses the role of excess Al and deposition rate in reducing the doping efficiency of Al+3 cations in Al-doped ZnO (AZO) films. In this regard, AZO films were deposited on the soda lime glass substrates using co-sputtering from ceramic AZO/ZnO and metallic Al targets. Whereas power to ZnO/AZO target was kept constant, power to Al target was varied to see the effect of varying Al concentration (and deposition rate) on its doping efficiency. Here, Al doping efficiency in ZnO is found to increase initially with increasing deposition rate and Al content, beyond which it decreased because of the formation of higher A lxOy in combination with increased trapped Al in the amorphous regions of these films. Moreover, a detailed discussion on the mechanism of the deposition rate and thereby induced variation in Al doping efficiency is discussed and then related to the optoelectronic properties of these films. Keywords Doping efficiency · Deposition rate · Al-doped ZnO · Co-sputtering · Optoelectronic properties
1 Introduction Deposition rate plays a significant role in optoelectronic industries as it decides the throughput of these materials [1]. As most of the commercially used optoelectronic materials are chemical compounds consisting of multiple elements, a change in the deposition rate for the growth of these compounds would alter their underlying mechanisms of film growth, thereby varying the stoichiometry, bond formation and affecting their optoelectronic properties. A detailed analysis on the deposition rate induced variation in the optoelectronic properties of these materials is thus necessary to understand and optimize the process conditions to grow films for specific requirements. To this end, here two series of AZO films were deposited on the soda lime glass (SLG) substrates using co-sputtering from ceramic ZnO (100 wt% ZnO) or AZO (98 wt% ZnO, 2 wt% A l 2O 3) Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00339-020-03705-0) contains supplementary material, which is available to authorized users. * Emila Panda [email protected] 1
Department of Materials Science and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gujarat 382355, India
and metallic Al targets. Whereas, power provided to the ZnO and/or AZO target was kept constant of 50 W, power provided to the Al target was varied from 0 to 40 W to see the effect of varying deposition rate (and Al concentration) on its doping efficiency in these AZO films, which defines their optoelectronic properties. Followed by deposition, a wide range of characterization techniques were used to understand the mechanism of these films formation and also the reason behind effective doping of Al+3 cations in Zn+2 lattice sites. AZO is
Data Loading...
