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Pentacene OFETs

Figure 20.1 Sample geometries (a) Schematic contact layout for bottom-contacted pentacene OFETs, and (b) for top-contacted pentacene OFETs, with sample holder and electrical contacts. Figure 20.1 Sample geometries (a) Schematic contact layout for bottom-contacted pentacene OFETs, and (b) for top-contacted pentacene OFETs, with sample holder and electrical contacts.
Figure 20.4 (a) Results of a two-dimensional simulation of a pentacene OFET with geometric parameters close to the bottom-contacted device investigated with potentiometry, for // = 0.014 cm V s and an effective injection barrier of 0.42 eV, and (b) construction of an injection barrier of 0.73 eV out of the effective barrier of 0.42 eV and the electric field close to the source contact, as obtained in the simulation for a gate voltage of Uq = -30 V. [Pg.434]

In the following, we present the results of charge transient spectroscopy performed on the bottom contacted pentacene OFETs, a variant of DLTS where the current transient is integrated, yielding a charge transient [43, 44]. In combination with capacitance DLTS, this technique can also provide information on the depth profile of the trap distribution [45]. [Pg.436]

If the density of states (DOS) of the trap states were broadened, the charge transient Q(t) would not follow a single exponential rise as in Eq. (6), resulting in turn in broadened QTS traces with respect to the fit based on Eqs. (5), (6). Such a behaviour was observed for polymer-based diodes [20] and for phthalocyanines [46], but for our bottom-contacted pentacene OFETs, we found no evidence of a broadened DOS of the trap states with a corresponding distribution of de-trapping rates. [Pg.437]

The comparative in situ electrical measurements on the top-contacted pentacene OFETs with and without OTS treatment reveal an increased charge car-... [Pg.438]

Comparing the potentiometry measurements in Figure 20.8 obtained on top-contacted pentacene OFETs with the data for the bottom-contacted sample in Figure 20.2, the most striking difference is the absence of a substantial potential drop close to the source contact. The reduction of the contact resistance... [Pg.439]

Figure 20.9 (a) Comparison of electric field distribution with (sobd bnes) and without (dashed) OTS treatment of the gate oxide, (b) AFM picture of a pentacene OFET with untreated gate oxide, revealing a channel length of about 17 pm. [Pg.441]

Figure 20.10 QTS data for a top-contacted pentacene OFET withont OTS treatment, withi = 17 pm and W= 3000 pm. Figure 20.10 QTS data for a top-contacted pentacene OFET withont OTS treatment, withi = 17 pm and W= 3000 pm.
Illustrated in Figure 24.4 is the output characteristic of a pentacene OFET with Au drain-source electrodes and a 200 nm Si02 dielectric [32]. The OFET exhibits unipolar p-type behaviour with a hole mobility = 0.165 cmWs, a threshold of = -4.5 V as well as an On/Off ratio of >10. These parameters have been derived from the respective transfer characteristics. The absence of an s-shaped feature in the linear range of the characteristic indicates ohmic contacts between the Au electrodes and the pentacene active layer. This is attributed to the good matching of the ionisation potential of the organic semiconductor and the Au work frmction. However, employing a Ca drain-soirrce metallisation, with an otherwise identical OFET device structure, the transistor did not exhibit any current in the electron accumulation mode. This is unexpected, since the metal work frmction is well matched to the electron affinity of pentacene. [Pg.519]

Figure 24.4 Output characteristic for a pentacene OFET, realised using Au drain-source contacts and a pristine Si02 dielectric [32]. Figure 24.4 Output characteristic for a pentacene OFET, realised using Au drain-source contacts and a pristine Si02 dielectric [32].
Empolying such a Ca passivated Si02 insulator in combination with Ca drain-source electrodes, n-t5q3c pentacene OFETs can be realised as has been demonstrated by Ahles et al. [29]. This, however, holds only for thin Ca layers as will be shown in the following, where the influence of the Ca passivation thickness on the electron transport in pentacene OFETs is discussed. Illustrated in Figiue 24.8 is the electron field effect mobility in dependence of the Ca thickness. By eonsidering the mobility of pristine devices, which have not... [Pg.523]

In order to rule out an improved deviee performance due to heat indueed morphological changes, the following experiment was conducted. A p-type pentacene OFET without Ca passivation and Au source-drain contacts was annealed at T = 160 °C for t = 1 h, in an inert nitrogen atmosphere. Even though... [Pg.526]

Table 24.3 Comparison of device parameters for a standard p-type pentacene OFET, utilising a pristine Si02 dielectric with Au source-drain contacts and the respective thermally treated device. Table 24.3 Comparison of device parameters for a standard p-type pentacene OFET, utilising a pristine Si02 dielectric with Au source-drain contacts and the respective thermally treated device.
Figure 24.14 (a) Drain current as a function of Fp for a UV modified pentacene OFET in the electron accumulation mode. Inset threshold voltage shift between the and 8 successive measurement cycles at Fg = 0V. (h) Electron and hole accumulation mode for a UV modified OFET during the 1 and after the 8 measurement cycle. The OFETs were reahsed using Ca electrodes. [Pg.532]

Interface Modification of Pentacene OFET Gate Dielectrics... [Pg.162]


See other pages where Pentacene OFETs is mentioned: [Pg.133]    [Pg.314]    [Pg.415]    [Pg.497]    [Pg.378]    [Pg.427]    [Pg.428]    [Pg.428]    [Pg.429]    [Pg.429]    [Pg.430]    [Pg.430]    [Pg.431]    [Pg.431]    [Pg.431]    [Pg.432]    [Pg.434]    [Pg.435]    [Pg.436]    [Pg.437]    [Pg.438]    [Pg.438]    [Pg.439]    [Pg.440]    [Pg.441]    [Pg.442]    [Pg.517]    [Pg.520]    [Pg.528]    [Pg.528]    [Pg.535]    [Pg.535]    [Pg.535]   
See also in sourсe #XX -- [ Pg.279 ]

See also in sourсe #XX -- [ Pg.245 ]




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OFETs

Pentacene OFETs With Bottom Contacts

Pentacenes

Top-Contacted Pentacene OFETs

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