| 摘要 |
782,663. Photo-electric arrangements. WESTERN ELECTRIC CO., Inc. March 4, 1955 [March 5, 1954], No. 6455/55. Class 40 (3) [Also in Groups XXXV and XXXVI] A photo-sensitive element for converting solar radiation into electrical energy comprises a silicon body having a PN junction, the thickness of either the p or n zone being of the order of the diffusion length and small enough to allow the radiation to reach the junction. The device may be associated with a storage battery, a rectifier also being provided so that the device may charge the battery but the battery cannot discharge through the device. Fig. 1 shows a body 11 of n-type silicon having a thin surrounding p-type layer 13. The p region may be produced by heating an n-type silicon wafer to 1000‹ C. for 5¢ hours in an atmosphere of boron trichloride. Low-resistance connections 18 and 19 to the p layer can be provided by electroplating rhodium direct on to the boron diffused layer without first roughening the surface. The p layer is partially removed to allow low-resistance connection 17 to be provided to the n-type body, and insulation 21 and 22 is provided to reduce current leakage. Solar radiation on surface 14 reaches the PN junction, and can produce an electrical output of approximately one watt. Reflection losses can be reduced by coating the silicon with a layer 20 of material having a refractive index between that of silicon and of the atmosphere. Such material may consist of polystyrene or silicon dioxide. A plurality of cells may be connected in series or parallel, and arranged in a non-horizontal position with reflector means for concentrating the solar energy. Specifications 692,250 and 782,662, [Group XXXVI], are referred to. |
