Chin. Phys. B, 2008, Vol. 17(10): 3822-3826    DOI: 10.1088/1674-1056/17/10/047
 CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES Prev   Next

# The effect of annealing temperature and film thickness on the phase of pentacene on the p+-Si substrate

Yuan Guang-Cai(袁广才), Xu Zheng(徐征), Zhao Su-Ling(赵谡玲), Zhang Fu-Jun(张福俊), Huang Jin-Zhao(黄金昭), Huang Jin-Ying (黄金英), Tian Xue-Yan(田雪雁), and Xu Xu-Rong (徐叙瑢)
Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University), Ministry of Education, Beijing 100044, China
Abstract  This paper investigates the morphology and crystallization properties of the two crystalline phases of pentacene grown by thermal evaporation on p$^+$-Si substrates at room temperature by the methods of atomic force microscopy and x-ray diffraction. This kind of substrate induces a thin film phase and a triclinic phase which are formed directly onto p$^+$-Si substrates and constitute a layer consisting of faceted grains with a step height between terraces of 15.8\,{\AA} (1\,\AA=0.1\,nm) and 14.9\,{\AA}, respectively. Above the critical thickness of the thin film phase, lamellar structures are found with an increasing fraction with the increase of the film thickness. When the film thickness is fixed, the fraction of lamellar structures increases with the increase of annealing temperature. These lamellar structures are identified as the second phase with a interplanar distance of 14.9\,{\AA} corresponding to the pentacene triclinic phase. Furthermore, the thin film phase consisting of several micrometre sized uniformly oriented grains at an annealing temperature of less than 80${^\circ}$C and a deposition rate of 0.6\,{\AA}/s is observed.
Keywords:  pentacene      morphology      crystalline phase      thin-film transistors
Received:  14 November 2007      Revised:  11 April 2008      Accepted manuscript online:
 PACS: 68.55.-a (Thin film structure and morphology) 81.40.Ef (Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization) 81.15.Ef 68.37.Ps (Atomic force microscopy (AFM)) 68.55.Nq (Composition and phase identification) 68.35.B- (Structure of clean surfaces (and surface reconstruction))
Fund: Project supported by the National High Technology Research and Development Program (863 plan) of China (Grant No 2006AA03Z0412), the National Natural Science Foundation of China (Grant Nos 60576016 and 10774013), the Excellent Doctor's Science and Technology Innovation Foundation of Beijing Jiaotong University (Grant No 48024), The Research Fund for the Youth Scholars of the Doctoral Program of Higher Education (Grant No 20070004031), the Beijing NOVA program (Grant No 2007A024), the Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry；the Foundation of Beijing Jiaotong University (Grant No 2005SM057).