GB1335271A - Radiovoltaic electricity generators - Google Patents

Abstract

1335271 Semi-conductor devices COMMISSARIAT A L'ENERGIE ATOMIQUE 25 May 1971 [28 May 1970] 16868/71 Heading H1K A radioisotope powered electric generator comprises a beta-source and a radiovoltaic cell consisting of a thin layer of polycrystalline semiconductor material containing a PN junction. As shown, Fig. 1, a power module comprises a layer 24 of N type polycrystalline CdTe or ZnTe doped with In and a P type layer of CuTe on which is placed a beta-source 22 comprising a stainless steel disc vapour coated with a Ti layer containing tritium in its hydride form. The semi-conductor layer may be deposited on a Mo film. A plurality of such modules are insulated by discs 26 of mica or plastics film, connected in a series-parallel arrangement and enclosed in a stainless steel housing 10, 12 on to which is welded a cover 14 having a centre contact 18 insulated by an alumina ring 20. The casing is exhausted and sealed or may be filled with He, Ar or Xe. In a modification, Fig. 3 (not shown), a layer of Ti is deposited on the semi-conductor layer by ionic bombardment and is then cold impregnated with tritium to form the beta-source. An electrode grid is sprayed on to the Ti layer. In a second embodiment, Figs. 4 to 6 (not shown) a plurality of cells are produced by depositing polycrystalline semi-conductor on to adjacent longitudinally arranged areas of a long strip of Mo and rolling this strip together with a strip-form beta-source and a mica insulating strip into a coil which is enclosed in a casing. The beta-source effectively connects the cells in parallel. In a modification, Fig. 7 (not shown) the Mo strip is provided with a continuous semiconductor layer which contains tritium over some of its depth. The beta-source may also be Ni-63 and the semi-conductor material may also be CdS.