Characterization of Al/In:ZnO/p-Si photodiodes for various In doped level to ZnO interfacial layers

Abstract

The detection of the light by a device is so important for industrial applications such as energy harvesting, sensing and switching. For that aim, we have introduced various In doped (0%, 0.1%, 0.5% and 1.0%) nanostructure ZnO thin films which was prepared by the sol-gel spin coating technique as interfacial materials between the Al metal and p-type Si for investigation photodetection properties of the material. According to morphological results of the In doped ZnO thin films at AFM, undoped and In doped ZnO thin films formed as fiber like structures. The obtained optical band gap energy for undoped, 0.1%, 0.5% and 1.0% In doped ZnO thin films were determined as 3.293 eV, 3.283 eV, 3.272 eV and 3.263 eV, respectively. The Al/In:ZnO/p-Si devices were characterized with I–V and C–V measurements. The I–V data was acquired under various illumination conditions to see the response of the devices to the light. The I–V characteristics have revealed that the devices have high ideality factors and, their values usually increased with increasing In doping level, but the rectifying properties decreased. In addition, barrier heights and series resistance values decreased with increasing In doping level. Also, the device parameters were calculated via Cheung and Norde methods for accuracy of the results. The current transient measurements highlighted that In doping provided to increase of light response. The C–V measurements have imparted that the capacitance values are strong function of the frequency and voltage for various In doping level. The devices can be thought and improved as photodiode and photodetector applications in the industry.