凯发

Low frequency "1/f noise" is a major limitation on the performance of nanoscale electronic devices. It is very difficult to obtain low noise level in graphene field effect transistor due to the two-dimensional nature of graphene, which can be severely affected by the surrounding environment. We fabricated a top-gated graphene field effect transistor with an ultra-low 1/f noise level of 1.8×10-12 µm2Hz-1 at f=10 Hz, which is three orders of magnitude smaller than that reported in other GFETs. The noise has the least value at Dirac point, it then increases fast when the current deviates from that at Dirac point, the noise slightly decreases at large current. The phenomenon can be understood by the carrier-number-fluctuation induced low frequency noise, which caused by the trapping and detrapping processes of the carriers in conducting channel through tunneling. Further analysis suggests that the value of effect trap density in our device is not constant but depends on the location of Fermi level in graphene channel. The obtained results are important for the proposed graphene applications in analog, mixed-signal, and radio-frequency systems, integrated circuits and sensors.