Review of tailoring ZnO for optoelectronics through atomic layer deposition experimental variables

Atomic layer deposition (ALD) is an increasingly popular thin film deposition technique which offers unique large area capability combined with excellent conformality, thus ALD will likely be important in the development of next generation optoelectronic devices. Such device platforms include solar cells, thin film transistors and light emitting diodes, and in all of these technologies one material is frequently used - zinc oxide (ZnO) - owing to its excellent electrical and optical properties combined with earth abundance. The approaches and achievements in tailoring the properties of ALD ZnO are discussed. Key process variables include deposition temperature and purge times as well dopant incorporation, with particular attention paid to tuning band alignment and carrier concentrations (focusing on lower carrier concentration applications).This review was submitted as part of the 2016 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged.