High Power Needs for Commercial Satellites
This overview paper presents estimates of the photovoltaic power systems needed on commercial communications spacecraft in the year 2000. These are developed in the form of power requirements based on extrapolation of the historical growth in communications traffic and are about 5 to 15 kW. The paper also addresses the key technology drivers in these photovoltaic systems. The importance of reducing mass in the power system is described in terms of the tradeoff with communications systems mass to maximize communications revenue. It surveys solar array components and subsystems to meet these future requirements and attempts to identify the development candidates with a large payoff potential and a high probability of successful development.
Large scale OM-CVD growth of GaAs solar cells
Developpement par Applied Solar Energy Corporate d'une technologie pour la production en masse de cellules solaires AlGaAs/GaAs a haut rendement. Rendement de cellules de 2×2 cm preparees suivant cette technologie
Diffusion length measurement by means of ionizing radiation
Penetrating radiation in the form of high-energy electrons, heavy particles, and gamma rays may be used to determine minority-carrier diffusion lengths in semiconductor materials containing junctions by measuring the radiation-induced short circuit current. The electron-beam method yields an accurate absolute determination of diffusion length once the carrier-generation rate as a function of depth in the material has been measured. A series of such experiments is described for silicon solar cells utilizing electrons ranging in energy from 0.61 Mev to 1.16 Mev. A resultant maximum generation rate of 2.25 × 106 ± 5 per cent carriers/cm per incident 1 Mev electron is obtained at a depth of 0.096 gm/cm2. Measurements with 16.8 Mev and 130 Mev protons, and Co60 gamma rays are found to be in good agreement with the electron-beam measurements. An experimental arrangement is described which yields rapid and accurate diffusion-length measurements of solar cells under conditions in which radiation damage is negligible.