Thermal Conductivity Reduction at Inorganic–Organic Interfaces: From Regular Superlattices to Irregular Gradient Layer Sequences. Issue 11 (24th March 2018)

• Record Type: Journal Article
• Authors: Krahl, Fabian; Giri, Ashutosh; Tomko, John A.; Tynell, Tommi; Hopkins, Patrick E.; Karppinen, Maarit
• Is Part Of: Advanced materials interfaces. Volume 5:Issue 11(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-03-24
• Subjects: ALD/MLD -- gradient material -- inorganic–organic interphases -- thermal conductivity -- thin‐film superlattice; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.201701692
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Nanoscale superlattice structures are known to significantly suppress the thermal conductivity in thin films due to phonon scattering at the interfaces of the mutually different layers. Here it is demonstrated that in addition to the number of interfaces, their spacing within the film can lead to a reduction in thermal conductivity. The proof‐of‐concept data are for ZnO/benzene thin films fabricated through sequential gas‐surface reactions in atomic/molecular layer precision using the atomic/molecular layer deposition technique. In comparison to similarly constructed regular superlattice thin films, thermal conductivity values that are of the same magnitude, or even lower, are achieved for hybrid ZnO/benzene thin films in which the inorganic and organic layers are arranged in a more irregular manner to form various gradient patterns. Abstract : In this article, thermal conductivity of ZnO thin films with ZnO/benzene interfaces are investigated. Thin films with disordered internal structure (gradient materials) are compared to thin films with an ordered internal structure (superlattices). It is shown that thin films with an intrinsic disordered gradient structure can be as efficient, or even better, in suppressing the thermal conductivity as their ordered superlattice counterparts.