| 摘要 |
Si body is prepd. by (a) providing a mass of molten Si contg. a single conductivity-type dopant in a container inert to molten Si, (b) gradually cooling Si to solidification point to form crystal centres at random locatilocations throughout the mass, (c) maintaining at solidification temp. until crystallites are enlarged to an average mean dia. at least 1mm and are randimly distributed in noncolumnar, nonlinear fashion throughout the mass and (d) cooling to ambient temp. Molten Si is pref. prepd. by (i) placing Si of indiscriminate grain size in the container, (ii) providing a nonoxidising atmos. about the container, (iii) heating to over Si m.pt. pref. using r.f. generator and (iv) adding dopant, either before heating or to the molten Si. Si is suitable for use as host material in photovoltaic cells, providing a photovoltaic response e.g. efficiency 10%, approaching that of single crystal Si. The structure so formed consists of large grains, generally average 2mm, range 1-4mm, with most defects at grain boundaries. |
