Photoresponse investigation of polycrystalline gallium antimonide (GaSb) thin films

Thin films of polycrystalline gallium antimonide (GaSb) were grown on widely available mica substrates using the physical vapor deposition method. The as-grown films contain grains of nano-scale with regular symmetries, as identified by x-ray diffraction and scanning electron microscope analysis. Two-terminal devices with coplanar electrodes were fabricated from the polycrystalline GaSb films; thus, the time dependent photoresponse property of the films was investigated by measuring the current density-voltage characteristics of devices. A significant photoresponse of the device was revealed by the linear dependence of the applied bias. Additionally, the transient behavior of the GaSb thin films was used to optimize growth temperatures of the films. This study shows that polycrystalline GaSb thin films on mica at 500 °C are suitable for high photoresponse and low noise IR photodetectors, thus proving to be a low cost solution for IR photodetectors.