The Enhancement of Laser-Induced Transverse Voltage in Tilted Bi2Sr2Co2Oy Thin Films with a Graphite Light Absorption Layer

Laser-induced transverse voltage effect is investigated in c-axis tilted Bi2Sr2Co2Oy thin films coated with a graphite layer by using three different laser sources with wavelength ranging from ultraviolet to near-infrared. Due to the transverse thermoelectric effect, voltage signals are detected when the film surface is irradiated by these three lasers and the voltage sensitivity is enhanced as a result of the increasing light absorption at the graphite layer. This work demonstrates that the graphite can be used as an effective absorption layer for fabrication of light detectors based on the photo-thermo-electric conversion.