Electrical and Optical Properties of Granular Semiconductor Thin Films and Their Applications tO Electronic Devices

In the former section of the present study，Si-SiO_2multi-layered thin films have been fabricated by ion beam sputtering deposition technique.The structure has been utilized for observing possible quantum-size effects which are expected to become significant when the thickness of Si layers within the multi-layered structure becomes thin enough。Unfortunately，infrared Raman spectroscopy has shown that the Si layer is non-crystalline or fine poly-crystalline states。In the latter section，crystalline Si fine particles have been prepared by both gas evaporation and arc discharge techniques.Strong photoluminescence with subbandgap photon energies has been observed in the Si fine particles thus prepared.After oxidation of the fine particles，the photoluminescence has become abovebandgap of Si，the band tail covering the visible light region。This blue shift has been explained by aquantum-size effect originated from Si quantum dots.Several fine structures noted in the photoluminescence spectra have been explained consistently by radiative recombination of electrons and holes within a three-dimensional quantum well taking into account the presence of both heavy and light holes。

In the former section of the present study, SiーSiO_2 multiーlayered thin films have been fabricated by ion beam sputtering deposition technique. The structure has been utilized for observing possible quantum-size effects which are expected to become significant when the thickness of Si layers within the multiーlayered structure becomes thin enough. Unfortunately, infrared Raman spectroscopy has shown that the Si layer is non-crystalline or fine poly-crystalline states. In the latter section, crystalline Si fine particles have been prepared by both gas evaporation and arc discharge techniques. Strong photoluminescence with subbandgap photon energies has been observed in the Si fine particles thus prepared. After oxidation of the fine particles, the photoluminescence has become abovebandgap of Si, the band tail covering the visible light region. This blue shift has been explained by aquantum-size effect originated from Si quantum dots. Several fine structures noted in the photoluminescence spectra have been explained consistently by radiative recombination of electrons and holes within a three-dimensional quantum well taking into account the presence of both heavy and light holes.