ISSN:0370-1972    

DOI:10.1002/pssb.2221900141

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221900142

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe striking photoluminescent properties of porous silicon nanostructures have received intense study since 1990. This literature review focuses on the large number of models proposed to account for efficient light emission. Two distinct luminescence bands in the visible spectral range have received most study. Strong evidence now exists that quantum confined carriers in crystalline Si can yield efficient red to green (‘S band’) luminescence. The blue (‘F band’) emission reported to date in oxidised porous Si is, however, unlikely to arise from quantum confinement

ISSN:0370-1972    

DOI:10.1002/pssb.2221900102

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221900144

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe ageing of porous silicon under ambient conditions must be taken into account in the design of optical devices using this material. The time dependence of the optical properties of porous silicon single layers and superlattices is studied in detail using reflectance spectroscopy. In the infrared the Si–H and Si–O vibrational modes are examined which reflect the state of thc internal surfaces. The optical properties in the visible and ultraviolet spectral range are investigated as well. Spectra are recorded on time scales ranging from minutes to months after sample preparation. The observed changes of the optical properties are discussed. It is verified that the stability of porosity superlattice filters in time can be improved significantly by thermal oxidat

ISSN:0370-1972    

DOI:10.1002/pssb.2221900103

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe fabrication of porous silicon (PS) with controlled pore size distributions is of importance for reproducible manufacturing as well as it may help to elucidate the origin of light emission from this material. The pore formation on p‐doped Si(111) surfaces is studied. For this purpose hydrogen passivated surfaces are prepared by wet chemical treatment. After introduction into UHV system a 1 × 1 LEED pattern is readily obtained without any further treatment. These surfaces are etched at the open circuit potential (OCP) in HF solutions with pH‐values ranging from 1 to 10. Atomic force microscopy is used to characterize the dependence of pore formation on time and acidity. It is found that narrow pore size distributions can be obtained when HF solutions with high pH‐values ar

ISSN:0370-1972    

DOI:10.1002/pssb.2221900104

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe basic problems of porous silicon (PS) transport, like long time constants, ageing, and the influence of contacts are discussed. The results of the steady‐state and transient photoconductivity on the self‐supporting p‐ and n‐type PS are presented and the resulting conclusions, related to the microstructure isotropy, trapping, and time‐dependent electric field redistribution are summarized. On the basis of the darkI–Ucharacteristics and their temperature dependencies the different volume and surface transport mechanisms are discussed. The compatibility of the models of explanation of the strong PS photoluminescence with our transport results i

ISSN:0370-1972    

DOI:10.1002/pssb.2221900105

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractVarious porous silicon (PS) properties are significantly modified by thermal annealing. For example, when a freshly prepared sample is annealed at 450°C, there are a significant reduction of the photoluminescence (PL) intensity, a change in the optical constants (refractive index and absorption coefficient), a sharp decrease in the material strain, hydrogen desorption, and change in the microstructure. The modification of all the parameters listed above (strain, PL, absorption coefficient, microstructure etc.) occurred for annealing temperatures between 350 and 450°C, and that is the same temperature range at which hydrogen is desorbed from the PS surface. The relationship between these parameters and the results of this comparison are discusse

ISSN:0370-1972    

DOI:10.1002/pssb.2221900106

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe photoluminescence (PL) properties of “porous silicon” prepared by spark erosion and of amorphous silicon carbon alloys. amorphous silicon carbon oxygen alloys and hydrogenated amorphous carbon prepared by CVD methods from liquid precursors are measured. Ellicient blue‐green PL is measured as a function of temperature up to 800 K. Optical absorption data in the high energy range (UV) are obtained from transmission measurements. Very low absorption coellicients in the visible spectral range are determined in light‐guiding thin film structures which are grown as a three‐layer sandwich on a silicon

ISSN:0370-1972    

DOI:10.1002/pssb.2221900107

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractPorous silicon layers are chemically grafted with trimethylsiloxy groups by exposure to hexamethyldisilazane (HMDS) vapors. After treatment, infrared spectroscopy reveals that part of the initially hydrogenated surface is actually modified. Luminescence of the porous layers appears to be little affected by the treatment. On strongly luminescent samples, the photocarriers exhibit the same infrared absorption as in hydrogenated or oxidized porous silicon, evidencing the similar involvement of localized states in the luminescence process. The treated porous silicon layers also exhibit an increased stability against aging in ambient, as compared to hydrogenated porous silicon. Furthermore, the modification can be removed by simple exposure to HF vapor, thereby restoring the initial hydrogenated surface.

ISSN:0370-1972    

DOI:10.1002/pssb.2221900108

出版商:WILEY‐VCH Verlag    

年代:1995

数据来源: WILEY