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A New Model Of Low Temperature Photoluminescence In Amorphous Semiconductors, Mathieu Kemp, Marvin Silver

Scanning Microscopy

Recent low temperature a-Si:H photoluminescence experiments show the presence of two peaks in the lifetime distribution, and a dependence of the efficiency on generation rate. These results contradict every existing model of amorphous semiconductor photoluminescence. The reason for the discrepancy is that every model predicts diffusive motion of the photo-generated pairs. We show how the inclusion of coulomb interaction between photocarriers, spin selection effects, and Auger recombination gives back agreement of theory with experiment. This new picture of the phenomenon also explains the transient behavior of the luminescence intensity.

Luminescence From Porous Silicon, Yasunori Mochizuki

Scanning Microscopy

Structural and optical properties of porous Si are reviewed with the main emphasis on the radiative recombination mechanisms. Behaviors of the visible photoluminescence and another intense luminescence process (the infrared luminescence) are discussed based on the available data provided by photoluminescence and related techniques. It is demonstrated that a further insight into the interrelation of these luminescence processes can be obtained by the optically-detected magnetic resonance method, in which non-radiative point defects (surface dangling bonds) are used as a local structural probe for the radiative states.

As for the model for the visible light emission, the implication of the quantum …

Diamond Luminescence, R. Heiderhoff, L. J. Balk

Scanning Microscopy

Luminescence spectroscopy is an established tool to investigate natural, high pressure synthesized, and chemical vapour deposited (CVD) diamond. The spectral range extends from 5.3 eV in the ultraviolet to approximately 1.2 eV in the near-infrared. More than 100 optical centres have been observed.

Since the early 1930's, semiconducting diamond for electronic devices has been of interest to science. The large bandgap (5.5 eV), low dielectric constant (5.7), and high thermal conductivity (about 5 times larger then that of Ag), as well as the superior charge-carrier transport properties, such as electron and hole mobility (µ^-: 2200 cm²/Vs, …

Can Photo- And Cathodoluminescence Be Regarded As Complementary Techniques?, S. Myhajlenko, R. A. Puechner, J. L. Edwards, D. B. Davito

Scanning Microscopy

Photoluminescence (PL) usually provides macroscopic, high quality spectroscopic data. Cathodoluminescence (CL), on the other hand, offers the same information with microscopic imaging. However, replicating PL signatures in a CL system is not straightforward since matching experimental conditions, such as temperature and excitation density, is difficult. The matter is further exacerbated by inherent differences in the nature of excitation: electrons versus photons. Our work with high purity semiconductors suggests that CL is generally more sensitive to excitation "circumstance" than PL. For example, electrons can cause sample charging and contamination-related phenomena that dramatically affect CL. Changes in surface attributes (e.g., by chemical …

Surface Recombination Velocity And Bulk Carrier Lifetime Measurement Of Silicon Crystals By Using Photoluminescence Time Decay, Karsten Thölmann, Masakazu Yamaguchi, Akihiro Yahata

Scanning Microscopy

The time decay for photoluminescence (PL) emitted from silicon crystals has been used to obtain both bulk carrier lifetime (Tb) and surface recombination velocity (S). Experimental results were interpreted with the assumptions that the sample was under a low-excitation condition and that the ratio of radiative to non-radiative recombination rates was constant throughout the carrier decay process. Analysis was applied to several wafers covered with different kinds of silicon dioxide (SiO₂). The results indicate that PL time decay measurement is effective to obtain the values of Tb and S.