PEMBUATAN TRANSISTOR EFEK MEDAN ORGANIK (OFET) BERBASIS FILM TIPIS CuPc UNTUK DETEKSI GAS CO2; FABRICATION OF ORGANIC FIELD EFFECT TRANSISTOR (OFET) BASED ON CuPc THIN FILM FOR CO2 GAS DETECTION

Sujarwata, Kusminarto

2015 | Tesis | FMIPA

This research aimed to fabricate a CuPc thin film-based organic field-effect transistor (OFET) with bottom-contact structure for detecting CO2 gas. The experiment was started by doing deposition of CuPc thin film on Si substrate which was, then, continued by having its characterization using X-RD and SEM. The result of the X-RD and SEM characterization was employed to define the optimum thin film which will be used in the process of OFET fabrication. Several OFETs were fabricated with various channel lengths: 100 ?m, 200 ?m and 300 ?m by using vacuum evaporator method, while the planning process was performed by lithography technique. The result showed that the CuPc thin film deposited with 45 A current was the optimum thin film. The steps of the OFET fabrication were as follows. It was started by blenching the substrat with etanol in an ultrasonic cleaner. It was, then, followed by the deposition of source and drain electrodes on the SiO2 substrate. The next step was doing the CuPc thin film deposition between source/drain. Finally, the gate deposition was carried out. The fabricated OFET was then characterized by using the El-Kahfi 100 to determine its output characteristic. The result indicated that the OFET can detect CO2 gas in active area, but in saturation area it cannot. The purpose of the CuPc thin film-based OFET test was to detect CO2 gas. The response time is gas sensor ability to recognize a detected gas, while the recovery time is the time taken by the sensor to return to its normal position. The response time of OFET with channel lengths of 100 ?m, 200 ?m and 300 ?m to CO2 test gas were (50.0 ? 0.1), (120 ? 1) s and (150 ? 1) s, while its recovery time were (60 ? 1) s, (101 ? 1) s and (119 ? 1) s respectively. These results showed that the OFET’s channel length influenced gas sensor’s response time: the shorter the channel length, the quicker the gas sensor’s response. The best gas sensor’s response time was at the shortest OFET’s channel length and, inversely, the longer channel length caused longer response time. This occured because the resistance of OFET with longer channel length will decrease slowly when the OFET was subjected by the gas. Prior to have the good response time, the fabrication of OFET, applied as a gas sensor, has to pay attention to its channel length.

Kata Kunci : N