PHOTOELECTRIC PROPERTIES OF lONR'ALLY HOMHAliDKl) SILICON 815 

 CONCLUDING REMARKS 



Those oxiK'iimonts have served not only to introduce us to some of the 

 phenomena inxolved in .semiconchictor harriers hut have also yielded 

 photo cells having desirable properties. These cells ha^ e a high degree of 

 stability and will stand treatment ruinous to most other cells. 'I'hey have 

 a very high current sensitivity to tungsten light and daj'lighl. They re- 

 (|uire no associated battery and can be mad(^ in large areas. I'lilikc \hc 

 material used in many types of photo cells, silicon does not ha\e the 

 disadvantage of scarcit^y. All tests to date indicate that an indefinitely 

 long life may be expected cNen inider extreme illumination. Fig. 11 sug- 

 gests that it may be possible to control to some extent the spectral re- 

 sponse in the region from the deep blue into the infra-red. The long wave 

 limit is set by the edge of the al)sorption characteristic. 



REFERENCES 



1. U. S. Patent No. 2,402,839, Filed Mar. 27, 1941. 

 U. S. Patent No. 2,402,662, Filed May 27, 1941. 

 U. S. Patent Xo. 2,443,542, Filed May 27, 1941. 



2. J. H. Scatf, H. C. Theuerer and E. E. Schumacher; also W. G. Pfaiin and J. H. 



Scaff, rrans. A. I. M. E., 185, pp. 383-392, 1949. 



3. P. S. Ohl, Bell System Tech. J., Jan., 1952. Also see this paper for more details 



regarding the method of preparing silicon. 



4. H. B. Briggs, Phys. Rec, 77, pp. 727-728, Mar. 1, 1950. 



