Panigrahi, Debdatta and Khatun, Salma and Khan, Anasua and Sahoo, Aditi and Chatterjee, Swastika and Pal, Amlan J and Dhar, Achintya (2019) Photosensitivity and charge injection dynamics of pentacene based thin-film transistors: influence of substrate temperature. Organic Electronics, 70. pp. 172-178. ISSN 1566-1199

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In this work, we have performed an in-depth analysis to investigate the effect of substrate temperature on the molecular packing arrangement and energy levels of pentacene films. We have also explored their influence on the charge injection mechanism and photosensing behaviour of pentacene-based organic field-effect transistors (OFETs). In this study, we find the contact resistance and photosensitivity of the devices to be severely influenced by the active layer processing condition owing to the aforementioned structural and energy level modifications. Contact resistance of the devices at metal-semiconductor interfaces was observed to be reduced significantly upon increase in the substrate temperature; however, above a certain temperature, formation of pentacene thin-films was severely affected and no transistor characteristics were obtained afterwards. Detailed experimental analysis and theoretical investigations revealed that the processing temperature could strongly influence the grain structure and unit cell volume of the pentacene molecules, which consequently enhanced the carrier injection across the interface through a control over carrier mobility and the distribution of electronic states in the proximity of Fermi energy. Furthermore, our study demonstrates the role of substrate temperature in effectively enhancing the photosensitivity of the transistors. This report thus represents a step forward towards understanding a correlation between the processing temperature and the dynamics of charge injection in pentacene based organic transistors. The results also illustrate the viability of using proper substrate temperature to achieve an efficient photosensitivity from OFET devices.

Item Type: Article
Subjects: Crystal Chemistry, Thermodynamics, Phase Equilibria
Depositing User: Bidhan Chaudhuri
Date Deposited: 15 Nov 2019 12:00
Last Modified: 15 Nov 2019 12:00

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