Response of tetrathiotetracene iodide films to temperature gradients in a spatially nonuniform current

The response of tetrathiotetracene iodide films to optical radiation from a He-Ne laser was studied. When the laser beam moved along the film, the response was greatest when the beam passed along the central line, and fell off rapidly toward the edges of the film. When a groove one-half the depth of the film was cut into the film, the response increased significantly and spread out over the entire length of the film, including regions away from the contacts. The suitable selection of thermal and electrical properties of the film in order to obtain a large response is also discussed.