Raman spectroscopy applied to reveal polycrystalline grain structures and carrier transport properties of organic semiconductor films: Application to pentacene-based organic transistors

Liang, Xin Wei; Chou, Wei‐Yang; Shen, Yu; Cao, Yang; Chang, Li Ren; Tang, Fu Ching

doi:10.1016/j.orgel.2008.12.002

Cited by 32 publications

(21 citation statements)

References 57 publications

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“…The Raman peaks at 1158 and 1179 cm −1 observed in the spectra arose from the C−H in-plane vibrations of a pentacene molecule and were assigned to the motions of atoms located at the ends and on both sides of the molecule, respectively. 41,42 The peak at 1158 cm −1 (v 0 band) splits into two vibrational modes centered at 1155 cm −1 (v 1 band) and 1163 cm −1 (v 2 band) due to intermolecular forces between adjacent molecules with different orientations in a unit cell, a phenomenon known as Davydov splitting. 42,43 The v 1 band was associated with inphase intermolecular coupling (twinning) vibrations of different pentacene molecules in a unit cell.…”

Section: Introductionmentioning

confidence: 99%

Surface-Order Mediated Assembly of π-Conjugated Molecules on Self-Assembled Monolayers with Controlled Grain Structures

et al. 2015

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This study systematically demonstrates the effects of the grain structure of crystalline self-assembled monolayers (SAMs) on the growth of organic semiconductor thin films on such monolayers, as well as the electrical characteristics of the resulting semiconductor films. The grain structure of the octadecyltrichlorosilane (OTS) monolayers could be tailored by constructing the monolayers at three different temperatures: −30°C (−30°C OTS), −5°C (−5°C OTS), and 20°C (20°C OTS). Among the three layers, −30°C OTS exhibited the largest crystalline grains and longestrange homogeneity of alkyl chain arrays. We found that pentacene films deposited on −30°C OTS monolayers show larger crystalline grains with higher degrees of crystallinity and lateral alignment compared to that of films deposited on −5°C OTS or 20°C OTS monolayers, following the surface characteristics of the underlying OTS monolayers. Furthermore, pentacene fieldeffect transistors fabricated with −30°C OTS monolayers showed lower charge trap densities and higher field-effect mobility values than devices fabricated using −5 or 20°C OTS monolayers. These results are explained in terms of enhanced quasiepitaxial growth of pentacene films on OTS monolayers with large grains.

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Section: Introductionmentioning

confidence: 99%

Surface-Order Mediated Assembly of π-Conjugated Molecules on Self-Assembled Monolayers with Controlled Grain Structures

et al. 2015

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“…We finally compare in Figure 6 the Raman spectra of the three pentacene polymorphs, so as to put in evidence the differences that allow to distinguish and identify them. The spectra are all unpolarized, to avoid possible confusion deriving from the different polarization of the bands [32,33]. Violet vertical lines underline the points of greater difference.…”

Section: Resultsmentioning

confidence: 99%

Raman Identification of Polymorphs in Pentacene Films

et al. 2016

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Abstract:We use Raman spectroscopy to characterize thin films of pentacene grown on Si/SiO x by Supersonic Molecular Beam Deposition (SuMBD). We find that films up to a thickness of about 781 Å (∼ 52 monolayers) all belong to the so-called thin-film (TF) phase. The appearance with strong intensity of some lattice phonons suggests that the films are characterized by good intra-layer order. A comparison of the Raman spectra in the lattice and CH bending spectral regions of the TF polymorph with the corresponding ones of the high-temperature (HT) and low-temperature (LT) bulk pentacene polymorphs provides a quick and nondestructive method to identify the different phases.

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“…It is found under tensile strain that the three vibration mode peaks of pentacene have shifted under the bending condition. According to the study that the Raman peak shift is related to the mobility improvement of pentacene [58,59], this photocurrent enhancement under the bending condition could be explained by the mobility improvement, given that tensile strain on the crystal lattice could increase the carriers' mobility of Si NM, as well [6,60]. To investigate the cause for this improved photocurrent and external quantum efficiency, the Raman confocal microscope is used to reflect the strain effect of the two materials.…”

Section: Flexible Photodetecting P-n Diode Between Pentacene and Si Nmmentioning

confidence: 99%

Semiconductor Nanomembrane-Based Light-Emitting and Photodetecting Devices

Liu

Zhou

2016

Photonics

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Abstract:Heterogeneous integration between silicon (Si), III-V group material and Germanium (Ge) is highly desirable to achieve monolithic photonic circuits. Transfer-printing and stacking between different semiconductor nanomembranes (NMs) enables more versatile combinations to realize high-performance light-emitting and photodetecting devices. In this paper, lasers, including vertical and edge-emitting structures, flexible light-emitting diode, photodetectors at visible and infrared wavelengths, as well as flexible photodetectors, are reviewed to demonstrate that the transfer-printed semiconductor nanomembrane stacked layers have a large variety of applications in integrated optoelectronic systems.

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Raman spectroscopy applied to reveal polycrystalline grain structures and carrier transport properties of organic semiconductor films: Application to pentacene-based organic transistors

Cited by 32 publications

References 57 publications

Surface-Order Mediated Assembly of π-Conjugated Molecules on Self-Assembled Monolayers with Controlled Grain Structures

Surface-Order Mediated Assembly of π-Conjugated Molecules on Self-Assembled Monolayers with Controlled Grain Structures

Raman Identification of Polymorphs in Pentacene Films

Semiconductor Nanomembrane-Based Light-Emitting and Photodetecting Devices

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