| Thin film transistors ?OTFTs? based on organic semiconductors have the characteristics of light weight, good flexibility and compatibility with plastic substrates,and are considered to be key components of future organic electronics technology in the fields of printed logic, displays and sensors. Despite these unique advantages, the vast majority of organic phototransistors reported so far work at high voltages exceeding | 20| V. which is a major technical bottleneck because most target devices require a lower voltage ?< | 10 | V?. Therefore, the successful application of organic thin film transistor technology in photoelectric sensors not only requires the development of high-performance device structure, but also need to develop organic thin film transistors with low operating voltage. Therefore, it is necessary to study the electrical characteristics and surface morphology of the dielectric layer in the low-voltage organic thin film transistor.The main work of this paper is as follows:?1? A method for preparing a smooth aluminum gate electrode was developed. The roughness of the stripped aluminum electrode was significantly reduced to 0.9 nm as compared to the thermal deposited aluminum with a roughness of 3.5 nm. After the anodic oxidation of the aluminum gate electrode, the roughness of the alumina was slightly increased to 1.50 nm. The stripped alumina modified with n-octadecylphosphonic acid is suitably used as an insulating layer, and the leakage current density is about 10-7 A / cm-2 at a voltage of -2 V and the capacitance density is 0.114 ?F / cm2. With the potentiostatic anodic oxidation of the stripped AlOx as an insulating layer, DNTT as a semiconductor,OTFT mobility up to 0.53 cm2 V-1 s-1. Since the semiconductor layer of the organic thin film transistor is DNTT, which has a light responsivity of the light at a wavelength of 450 nm. So, a low light intensity of 5 ?W / cm 2 can be detected by this phototransisitor?2? A low-voltage organic thin film transistor was prepared with PBIBDF-BT conjugated polymer as the semiconductor layer and n-octadecylphosphonic acid surface-modified anodized aluminum oxide as the insulating layer. The mobility was 0.038 cm2 V-1 s-1, the threshold voltage is 0.64 V, the on/off ratio is 3.25 × 103. Since the semiconductor layer of the organic thin film transistor is a PBIBDF-BT conjugated polymer, it has near-infrared sensing properties. The light was irradiated with light at a wavelength of 808 nm and a light intensity of 45.6 mW / cm2. The drain current was increased by 0.7 nA at the drain voltage VD=5 V and the gate voltage VG=1 V,which showed the performance of near infrared light.?3? ?6-azidohexyl? phosphonic acid was reacted with the alkyne end group PVP to modify the surface of the alumina as an insulating layer, and the ?6-azidohexyl?phosphonic acid having a functional group was successfully prepared, And the capacitance density was 2.52×10-6 F/cm2. The pentacene semiconductor layer is grown on the surface of the insulating layer to form a device which can operate at low voltage at 4 V. The mobility is 0.025 cm2 V.1 s.1; the threshold voltage is -1.4 V; the on/off ratio is 1 × 104; the subthreshold swing is 0.69 V / dec. Although this performance is not so good, but it can be used to verify the ?6-azidohexyl? phosphonic acid in the modified insulation surface properties of the application, in order to further prepare functional devices provide the basis. |
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