[0024] Example 1
[0025] The method for preparing graphene-based transistor channel materials by electrodeposition and the method for preparing graphene-based transistors is as follows:
[0026] In the first step, gold and chromium are plated on a 1x1cm glass substrate by evaporation coating. The thickness of chromium is controlled at about 0.3-1nm, and the thickness of gold is controlled at about 30-100nm, which serves as the gate and source of the transistor. , Drain, the distance between source and drain is 250μm;
[0027] In the second step, use tape to fix a size of 5mm×5mm on the channel. Disperse the graphene oxide in ultrapure water for 1h and then drip it on the fixed channel. The concentration of graphene oxide is 0.5mg/mL, which is natural After drying, the channel area of the transistor is modified with graphene oxide;
[0028] The third step, 1. Use the electrochemical workstation to set the scanning speed of the cyclic voltammetry to 50mV/s, and the number of scanning cycles is 20. The channel area of the transistor obtained in the second step is placed in a 0.5mg/mL graphene oxide solution The graphene is deposited as the channel of the transistor; 2. Use an electrochemical workstation to set the scanning speed of the cyclic voltammetry to 50mV/s, and the number of scanning cycles is 20. The channel area of the transistor obtained in the second step is set in 2mM chlorine. The gold and graphene composite material deposited in the gold acid solution is used as the channel of the transistor; 3. Use the electrochemical workstation to set the scanning speed of the cyclic voltammetry to 50mV/s, the scanning circle number is 20, and the second step is The channel area of the transistor is deposited in a 5mM zirconium oxychloride solution to obtain a zirconium dioxide and graphene composite material; 4. Use an electrochemical workstation to set the scanning speed of the cyclic voltammetry to 50mV/s, and the number of scanning cycles is 20. Depositing the channel region of the transistor obtained in the second step in a 20mM 3,4-ethylenedioxythiophene and 30mM sodium citrate solution to obtain a composite material of poly3,4-ethylenedioxythiophene and graphene as the channel of the transistor;
[0029] The fourth step is to set the V of the digital source meter DS =0.05V, V G From 0 to 2V, use Ag/AgCl electrode as the gate of the transistor, immerse the device in a buffer solution, and use a digital source meter to detect the transfer curve of the transistor.
[0030] by figure 1 It can be seen that the electrodeposited graphene on the transistor channel presents a corrugated structure; the electrodeposited gold and graphene composite material on the transistor channel shows that the gold nanoparticles are uniformly attached to the wrinkled graphene surface; the electrodeposited on the transistor channel two The zirconium oxide and graphene composite materials also present a pleated structure, mainly due to the poor crystallization performance of zirconium dioxide; the surface of the electrodeposited 3,4-ethylenedioxythiophene and graphene composite material on the transistor channel presents a network-like interwoven structure.
[0031] by figure 2 It can be seen that: electrodeposited graphene, gold and graphene composite materials, zirconium dioxide and graphene composite materials, poly 3,4-ethylenedioxythiophene and graphene composite materials have all obtained the unique "U" curve of graphene. At this time, the corresponding transistor sensors can be used for the actual qualitative or quantitative detection of hydrogen peroxide, glucose, methyl parathion, and acetaminophen. The "U" curve shows the bipolar behavior of graphene. The narrow band gap of graphene in aqueous solution makes it easy for electrons to transfer from the graphene valence band to the conduction band and combine with holes under the action of the gate voltage and the channel voltage. As the gate voltage increases, electrons fill up the holes and gradually accumulate, causing the carrier concentration to first decrease and then increase, resulting in a "U"-shaped curve, indicating that graphene is deposited.
[0032] Graphene is compounded with different materials as the channel, and the Dirac point shown by the transfer curve is different. figure 2 In (A), the Dirac point of the transistor transfer curve with electrodeposited graphene as the channel is 0.7V; figure 2 In (B), the Dirac point of the transistor transfer curve with the electrodeposited gold and graphene composite as the channel is 1.17V; figure 2 In (C), the Dirac point of the transistor transfer curve with the electrodeposited zirconium dioxide and graphene composite as the channel is 1.1V; figure 2 In (D), the Dirac point of the transistor transfer curve of the electrodeposited poly3,4-ethylenedioxythiophene and graphene composite as the channel is 1.05V.
