Electronic noise in photoconducting insulators

✍ Scribed by K.M. Van Vliet; J. Blok

• Publisher: Elsevier Science
• Year: 1956
• Weight: 744 KB
• Volume: 22
• Category: Article
• ISSN: 0031-8914
• DOI: 10.1016/s0031-8914(56)80063-3

✦ Synopsis

The noise caused by fluctuations in the number of free electrons is computed for photoconductors of the recombination type. First a discussion of the fluctuations in the incident photon stream is given and the resulting photo-induced noise is calculated. It is shown that these fluctuations do not entirely determine the ultimate sensitivity; besides optical generations of free electrons other transitions also contribute to the noise. In a model without localized levels, such as traps etc., the total noise is twice as large as the photo-induced noise, for all frequencies. Next a discussion is given for a photoconductor according to the model of K 1 a s e n s-S c h 6 n. The spectrum of the photoinduced noise does not get the same shape as the total noise spectrum. In both spectra the same relaxation times occur but the partition over the various terms is different. Finally approximations are made for excitation of electrons from activator levels and from the valence band at low and high light intensities.