The Growth Of Ge/Si Quantum Dots By Ion Beam Sputtering And The Initial Research Of Its Photoresistance

Quantum dots is a low dimension material which carrier strongly restricted in three dimensional space dimension. It’s exciton binding energy is much greater than its bulk material, This unique optoelectronic properties has a wide spread application in the field of photoelectric field, especially in the single electron devices, optoelectronic and microelectronic devices production areas. The Si base self-assembly Ge QDs material is easy to be combined with traditional Si base integrated circuit, which is becoming a hot spot of research in recent years.Based on self-assembly SK growth mode of Ge/Si material, we produce a single-layer and multilayer Ge/Si quantum dots material by using the ion beam sputtering apparatus and investigated material properties of surface morphology and crystalline degree at different annealing time and different buffer layer temperature. A preliminary attempt to an optical device (the photoresistor) was conducted on basis of multilayer quantum dot material. The whole research divides into the following aspects:1.We prepare a series of monolayer Ge/Si nano-islands material under 700 ℃ Si buffer layer conditions by ion beam sputtering device. AFM and Raman tests find that with increasing annealing time, bottom width and density of the nano-islands exhibit Ostwald ripening mechanism, but the annealing does not eliminate the amorphous component in the samples and the density of nano-islands is not very high.2.In order to obtain high-quality and crystallized quantum dots, we increase the Si buffer layer temperature to 800℃,getting the crystallized Si buffer layer with smooth surface. With more Ge deposition above the 800℃ Si buffer layer,we get a series of monolayer Ge/Si nano-islands materials with different annealing time. AFM and Raman tests find that the density of nano-islands is significantly improved under above condition.With increasing of annealing time, the content of Ge in nano-islands gradually increase, GeSi intermixing weaken and amorphous components disappear, thereby obtaining growth parameters for preparing high-quality and high density monolayer Ge/Si quantum dots.3.Multilayer quantum dots material is prepared based on the preferred monolayer quantum dot growth parameters. This multilayer quantum dots material adding the electrode is used for a active layer of photosensitive resistance device.IV test of the device shows that current under the 780 nm light conditions is significantly higher than the dark conditions, but the current value is larger than other devices.The reason may be that the large size of device and rough production process lead to the Al atoms in the electrode breakdown the device in the vertical direction, reducing device resistance greatly...