Graphene has received intensive attention in recent years because of the special physical and chemical properties. However, up to now graphene has not been widely used in optoelectronic fields yet, which is mainly caused by its semimetal properties. Therefore, changing its properties from semimetal to semiconductor is becoming a focal point. Recently, aiming at tuning the energy band of graphene, we have carried out systematic studies on the preparations of graphene based materials and devices, the CVD growth techniques of monolayer and double layer graphenes have been developed, the large-area doped graphene films have been fabricated to tune the structure-related optical and electrical properties. A novel graphene oxide (GO) preparation method namely “Tang-Lau method” has been invented, the graphene quantum dots growths by microwave assisted hydrothermal method and “Soft-Template method” have been developed, the Cl, S and K doped graphene quantum dots preparations by hydrothermal methods have also been invented. Systematic investigations have been carried out for the effect of preparation parameters on the properties of graphene based materials, the effects of size, doping elements on the energy level of graphene based materials have been explored and discussed. Based on the semiconducting graphene based materials, some novel room temperature photodetectors covering detection wavebands from UV, Vis and NIR have been designed and fabricated.
Amorphous HgCdTe (α-HgCdTe or α-MCT)films on glass substrate were deposited by RF magnetron sputtering
technology, amorphous structure of MCT films were studied by XRD and AFM technology, and the "growth window" of
α-MCT was obtained. FTIR technology was used to study the optics properties of amorphous MCT films, absorption
coefficient of amorphous MCT films (~8×10<sup>4</sup>cm<sup>-1</sup>) was obtained and we also observed three absorption regions near
the optical gap of amorphous MCT, the optical gap of our a-MCT film is about 0.83eV. The transition of amorphous
HgCdTe into crystal HgCdTe happened when the annealing temperature was higher than 130°C.