Experimental observation of oxygen-related defect state in pentacene thin films

Abstract

The authors report on a metastable defect observed in pentacene thin films. The defect, which is\ud characterized by a hole trap at Ev+0.6 eV and attempt-to-escape frequency of 5x1012 s−1, can be\ud reversibly created/removed under a negative/positive bias voltage applied to the aluminum/\ud pentacene Schottky diode at room temperature in air. Annealing the sample in vacuum at 360 K\ud removes the defect and prevents its creation by application of any bias voltage in vacuum.\ud Considering recent calculations of defects in pentacene the authors assume that the defect is formed\ud by replacing one of the hydrogen atoms by an oxygen atom (C22 H13 O).Peer Reviewe

Defect states in pentacene thin films prepared by thermal evaporation and Langmuir–Blodgett technique

“…It means the crossover of the Fermi level and deep-level does not approach the metal/semiconductor interface. We associate the deep-level of PTFs deposited by thermal evaporation at the deposition rate of 1 Å /s also with the defect formed in pentacene molecule by replacing one of the hydrogen atoms by an oxygen atom (O H defect) [13]. In contrast to films deposited at a rate of about 10 Å /s and characterized by a metastable deep-level at E v + 0.60 eV, the present defect cannot be removed by annealing in vacuum.…”

Photoexcited carrier relaxation dynamics in pentacene probed by ultrafast optical spectroscopy: Influence of morphology on relaxation processes

“…In order to successfully implement organic materials in these technologies it is vital to understand the photoconductive properties as well as the nature of the photogenerated states including their relaxation dynamics. Furthermore, it is important to understand the nature of defects and impurities, the presence of which may obscure the study of intrinsic properties and inhibit device performance [9,10].…”

Multiple-trapping in pentacene field-effect transistors with a nanoparticles self-assembled monolayer

“…2 The trap states as well as their influence on the charge transport have been investigated experimentally as well as via simulations, 3 and from there the energy levels and relaxation (release) times were estimated for most common organic semiconductors. 2,[4][5][6] On the contrary, charge storage is required for the memory devices. [7][8][9] Recently, the deposition of nanoparticles (NPs) at organic semiconductor-gate insulator interface was successfully used to achieve the charge retention.…”