Field effect transistor photodetector based on graphene and perovskite quantum dots

Graphene is an attractive optoelectronic material for various optoelectronic devices, especially in the field of photoelectric detection due to its high carrier mobility and fast response time. However, the relatively low light absorption cross-section and fast electron-hole recombination rate can lead to rapid exciton annihilation and small light gain, which restrict the commercial applications of pure graphene-based photodetector. The perovskite has attracted much attention because of its high photoelectric conversion efficiency in the field of solar cells. The perovskite has the advantages of long carrier diffusion distance and high optical absorption coefficient, which can effectively make up for the shortcomings of pure graphene-based field-effect transistor. In this work, a field-effect transistor photodetector is demonstrated with the combination of graphene and halide perovskite quantum dots (CsPbI3) serving as conductive channel materials. The graphene is prepared by plasma enhanced chemical vapor deposition, and the quantum dots are CsPbI3 perovskite. The electrical properties of graphene and pure graphene-based field-effect transistor are detected and analyzed by using the Raman spectrum. The results show that the graphene has good intrinsic electrical properties. Unlike previous report in which bulk perovskite was used, the perovskite quantum dot field-effect transistor photodetector has an obvious light response to 400 nm signal light, and shows the excellent photoelectrical performance. Under the illumination of 400 nm light, the signal light could be detected steadily and repeatedly by the graphene-perovskite quantum dot photodetector and converted into photocurrent. The photocurrent of the photodetector has a rapid rise, and the maximum value can reach 64 mu A at a light power of 12 mu W. The corresponding responsivity is 6.4 A.W-1, which is two orders of magnitude higher than that of the general single graphene photodetector (10(-2) A.W-1), and it is also higher than that of perovskite-based photodetector (0.4 A.W-1). In addition, the photoconductive gain and detectivity arrive at 3.7 x 10(4) and 6 x 10(7) Jones (1 Jones = 1 cm.Hz(1/2).W-1), respectively. The results of this study demonstrate that the graphene-perovskite quantum dot photodetector can be a promising candidate for commercial UV light detectors.