Displacement of Photoelectrons and Positive Holes in Sheet Crystals of Silver Bromide as Shown by Development Techniques

The mobility of electrons in unannealed, large, thin crystals of silver bromide made from the melt was measured from the displacement of latent‐image centers formed by flash exposures synchronized with pulsed electric fields; an etching‐development technique was used to locate the latent image as reduced silver. Similarly, the motion of positive holes in the crystals was determined by the hole‐induced destruction of previously introduced latent‐image centers or fog centers, which, on development, yielded a bleached image against a background of reduced silver. At 30°C, the electron mobility in these crystals was 66 cm2 V—1 sec—1, and their lifetime about 0.3 μsec; the mobility of the positive holes was 1.7 cm2 V—1 sec—1 and their lifetime in the undisturbed crystal was greater than 10 μsec.Even in the absence of positive holes, the formation of latent image on a surface of silver bromide may be greatly facilitated by the presence of a sensitizer, such as silver sulfide. In such a case, silver sulfide appe...