Layered cobalt oxide thin films with tilted structures exhibit large light-induced transverse voltage signals due to the
transverse thermoelectric effect and have great potential applications in uncooled broad-band light detectors. In this
paper, we investigated the photoresponse in c-axis tilted Bi2Sr2Co2Oy thin films coated with a layer of nano-structured silver light absorber by using a 532 nm continuous wave laser as the incident light. The incidence direction of the laser beam was directly perpendicular to the sample surface. The laser spot was located at the centre position between the two electrodes and its diameter was about 2 mm. The induced lateral voltage signals were recorded using a 2400 Keithley source meter. Open-circuit voltage signals were observed when the sample surface was illuminated by the 532 nmradiation. Appropriate lateral size and thickness of the nano-structured silver layer can increase the photo-thermal-electric conversion efficiency in this photoresponse process due to the effective absorption of the light at the absorption layer, leading to the improvement in voltage sensitivity. The result offers important guidance of designing the light absorption layer for high performance broad-band light detectors based on the light-induced transverse voltage effect.
this paper, we have prepared c-axis inclined NaxCoO2 thin films on 10° and 20° tilted c-Al2O3 substrates and studied its light-induced thermoelectric voltage effect by using an ultraviolet pulsed laser as light source. A giant open-circuit voltage signal with the peak voltage Vp of tens of voltage was observed when the film surface was illuminated by the 308 nm pulsed radiation, and the Vp increased linearly with the inclination angle as well as the laser energy on the film. In addition, we found that Ag doping in NaxCoO2 films can improve the sensitivity of the thermoelectric voltage signal. The results demonstrate that c-axis inclined NaxCoO2 thin film has a great potential application in the detection of weak ultraviolet pulsed radiation.