The modern single-layer selenium photo-electric cell

The development of selenium photo cells, culminating in the modern single layer CdO cell, is described and the basic working principle of these cells discussed. Mention is made of a new process called ¿Reactive Sputtering¿ which has shed much light on these questions and made the production of single layer cells a practical proposition. Other applications of Reactive Sputtering are briefly described and a few examples are given for the use of CdO selenium cells and of recently developed infra-red sensitive selenium cells.