Piezoelectric Properties of Zinc Oxide Thin Films Grown by Plasma‐Enhanced Atomic Layer Deposition. Issue 21 (22nd September 2020)

• Record Type: Journal Article
• Authors: Abu Ali, Taher; Pilz, Julian; Schäffner, Philipp; Kratzer, Markus; Teichert, Christian; Stadlober, Barbara; Coclite, Anna Maria
• Is Part Of: Physica status solidi. Volume 217:Issue 21(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-09-22
• Subjects: atomic layer deposition -- piezoelectricity -- thin films -- zinc oxide; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202000319
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Zinc oxide (ZnO) thin films are deposited by plasma‐enhanced atomic layer deposition (PE‐ALD). This deposition method allows depositing stoichiometric and highly resistive ZnO films at room temperature. Despite such important requirements for piezoelectricity being met, not much is known in literature about the piezoelectric properties of ZnO thin films (<70 nm) deposited by PE‐ALD. The films are grown at different substrate temperatures to investigate the effect on crystalline and piezoelectric properties. Films deposited on flexible poly(ethylene terephthalate) (PET) generated a higher piezoelectric current (>1.8 nA) and charge (>80 pC) compared with films deposited on glass (>0.3 nA and >30 pC) due to bending effects of the substrate when mechanically excited. Furthermore, increasing the substrate temperature, during deposition, enhances the growth along the (002) crystallographic orientation, which further strengthens the generated piezoelectric current signal for mechanical excitations along the ZnO film's c ‐axis. Abstract : The piezoelectric properties of ZnO thin films grown by plasma‐enhanced atomic layer deposition are investigated. Films grown on flexible substrates show enhanced piezoelectric output compared with rigid substrates due to possible bending effects. A higher growth temperature also leads to enhanced piezoelectric output due to preferential crystallographic orientation along the [002]‐axis.