Thermal change of organic light-emitting ALQ3 thin films

• Published in: Journal of thermal analysis and calorimetry 2010, Vol.99 (1), p.117-122
• Main Authors: Wang, Mei-Han, Konya, Takayuki, Yahata, Masahiro, Sawada, Yutaka, Kishi, Akira, Uchida, Takayuki, Lei, Hao, Hoshi, Yoichi, Sun, Li-Xian
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Calorimetry; Chemistry; Chemistry and Materials Science; Condensed matter: structure, mechanical and thermal properties; Density; Devices; Dielectric films; Diffraction; Exact sciences and technology; Failure; Inorganic Chemistry; Measurement Science and Instrumentation; Physical Chemistry; Physical properties of thin films, nonelectronic; Physics; Polymer Sciences; Surface roughness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal stability; thermal effects; Thick films; Thin films; X-rays
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-009-0486-5

A series of Alq3 thin films with the thicknesses of 50, 100, and 200 nm was deposited on Si substrates at room temperature using the thermal evaporation method. The thermal crystallization process of Alq3 thin films, especially 50 nm thick films, was successfully examined using high-temperature X-ray diffraction (HT-XRD) with the in-plane scan mode. Film thickness, density, and changes in surface roughness while heating were determined using X-ray reflectometry (XRR). The decreased density and increased surface roughness, which were accompanied by sublimation, indicate the instability of the Alq3 film. Thus, thermal instability is a major factor for device failure.