Volume 104, Issue 2, 15 July 2008
Index of content:
104(2008); http://dx.doi.org/10.1063/1.2958320View Description Hide Description
We report comparisons of measuredphotocurrent versus voltage curves of avalanche photodiodes(APDs) with those calculated using different hole and electron impact ionization coefficients. As the published impact ionization coefficients result in ionization rates that differ greatly in magnitude, the predicted breakdown voltages using these models vary by many volts. To this end, we investigate the breakdown voltage prediction capability of three prevailing impact ionization models in conjunction with several experiments. To obtain APD performance numerically, we developed a device simulator, which shows that the inclusion of proper electric field-dependent impact ionization rates can accurately predict a variety of measured current-voltage curves, breakdown voltages, and current multiplication rates.
Interlaboratory comparison of positron annihilation lifetime measurements for synthetic fused silica and polycarbonate104(2008); http://dx.doi.org/10.1063/1.2957074View Description Hide Description
Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.
104(2008); http://dx.doi.org/10.1063/1.2958316View Description Hide Description
Measurements of the dielectric constant of multiphased binary and ternary mixed alkali halides, which have found a multitude of applications in optical and electronic devices, have been recently reported in the temperature range from room temperature to 423 K. It was found that the temperature variation in the binary mixed crystal is drastically larger than in any other. We show that this variation can be quantitatively reproduced by means of a simple model, which does not contain any adjustable parameter and solely makes use of the properties of the end members, viz., NaCl and KBr.