Physical Vapor Growth Of Pentacene Thin Films And It's Growth Mechanism

This paper mainly discusses the method of Nitrogen- carrying , which can produces the even pentacene organic film in the level growing system of physical gas sediment, and also makes a state analyze of the thin film with SEM and then discusses the growing theory of it.The growing module of the organic semiconductor film can be divided into three classes as below:Island-shape growing module: As to many combinations of film and underlay, the deposit atom is capable of diffusing to some extent, as long as the temperature of the deposit is high enough. Then the growing module of the film behaves as Island-shape growing module. As the increase of deposit atom, many three-dimensional cores will assemble on the underlay, even if there isn't any advantageous position for the promoting of the core-forming. Layer-shape growing module: when the infiltration of deposit material and the underlay is good enough, the atom of the deposit material is inclined to produce linkage with the atom of the underlay.Transfer from Layer-shape to island-shape module: after the layer-shape growth of the first one or two atomic shell, the growing module transfers to island-shape module from layer-shape module. The physical mechanism of the transfer of module is complicated, but the reason can be attributed to the ebb and flow of diversified energy in the growing of the film.The factors those affect the growing and the quality of the film are as followed:(a)The roughness of the surface of the underlay. (b)The heating temperature. (c)The temperature of underlay. The air current in the experiment is also a key point that affects the growth of the film. It is obviously that the pentacene film shows the multi-layer growing module and the new pentacene film grows on the top of the island from the SEM image. After repeating experiments, it comes to the conclusion that even film will be formed when the heating temperature of 240 degree centigrade (the temperature of the underlay is 70 degree centigrade) and the air current keeps the volume of 0.04L/h.