Correlation of growth of pentacene films at various gas ambience conditions to organic field-effect transistor characteristics

Ambient-atmosphere annealing effect on the carrier conduction behavior based on the linear-regime transfer characteristics of pentacene thin film transistors

“…We deduce that large pentacene grains lead to higher mobility than small grains [41,42]. However, Chou et al [21] found that the grain size did not show any significant relation to μ. The results presented above show a strong correlation between the values of the spacing between molecules, qϕ t , a h and μ.…”

“…It is shown that the derived value of I on /I off increases with increasing annealing temperature reaching a maximum at 350 K, and then decreases with further increasing of annealing temperature beyond that point. It is believed that the most significant factor allowing obtaining higher μ and I on /I off is the improved quality of the pentacene layer [21]. On the other hand, it is found that an increase in annealing temperature leads to the shift of V TH towards positive gate-source voltages.…”

“…The performance of the pentacene-based OTFT is mainly determined by its carrier mobility, which is influenced by the electron-phonon coupling, crystallinity and intermolecular bonding nature [2][3][4]. Charge transport in organic semiconductors has been extensively studied [14][15][16][17][18][19][20][21]. The thermal annealing effect on carrier transport for the pentacene transistor was investigated [5][6][7][8][9].…”

Influence of Deposition Pressure on the Film Morphologies, Structures, and Mobilities for Different-Shaped Organic Semiconductors

“…Generally, the mobilities of OTFTs highly depend on the molecular packing and crystal grain sizes, which in turn rest on the chemical structures of the organic semiconductors, − deposition parameters, − and substrates. − Vacuum deposition is the most common techniques for preparing the thin films of small-molecule and oligomer semiconductors with the advantages of high uniformity and good reproducibility owing to the controllable deposition parameters, e.g., the substrate temperature ( T s ), deposition rate ( r dep ), and deposition pressures ( P dep ) (vacuum level). The influence of T s and r dep on the growth of organic thin films has been intensively studied, and increasing T s and/or decreasing r dep usually leads to a highly ordered film with larger grain sizes and fewer grain boundaries, which is the effective way to obtain high-performance devices. − Recent progresses indicate that P dep is also an important factor to influence the nucleation and growth of films, thereof the microstructures and performance of the corresponding OTFTs, as demonstrated by the growth of pentacene, copper phthalocyanine (CuPc), dicyanoquinonediimine, and tetracyanoquinodimethane films. − Our previous study showed that the morphologies and molecular packing structures of the disk-like CuPc semiconductor thin films could be effectively regulated simply by tuning P dep ; thus, the performance of the resulting CuPc TFTs could be conveniently optimized . In addition to the general results that larger grain size favors the higher mobility, both our experimental and theoretical results revealed that the interplanar spacing ( D value) of the film is also sensitive to the mobility of the CuPc TFTs, and the larger D value leads to the higher mobility.…”

The surface energy-dictated initial growth of a pentacene film on a polymeric adhesion layer for field-effect transistors

“…Among several transistor parameters, the field-effect mobility is the primary one because it governs the dynamic properties such as the driving frequency and the response time for various types of applications. Previously, it was reported that the field-effect mobility in the OFET strongly depends on the layer-by-layer growth and the resultant crystallinity of an organic semiconductor film [5][6][7][8]. Therefore, it is very important to control the initial growth of an organic semiconductor layer on a variety of substrates for practical applications.…”