Preparation of hexagonal nanoporous Al2O3/TiO2/TiN as a novel photodetector with high efficiency
Asmaa M. Elsayed, Mohamed Rabia, Mohamed Shaban, Arafa H. Aly, Ashour M. Ahmed
Abstract
Abstract The unique optical properties of metal nitrides enhance many photoelectrical applications. In this work, a novel photodetector based on TiO 2 /TiN nanotubes was deposited on a porous aluminum oxide template (PAOT) for light power intensity and wavelength detection. The PAOT was fabricated by the Ni-imprinting technique through a two-step anodization method. The TiO 2 /TiN layers were deposited by using atomic layer deposition and magnetron sputtering, respectively. The PAOT and PAOT/TiO 2 /TiN were characterized by several techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX). The PAOT has high-ordered hexagonal nanopores with dimensions ~ 320 nm pore diameter and ~ 61 nm interpore distance. The bandgap of PAOT/TiO 2 decreased from 3.1 to 2.2 eV with enhancing absorption of visible light after deposition of TiN on the PAOT/TiO 2 . The PAOT/TiO 2 /TiN as photodetector has a responsivity (R) and detectivity (D) of 450 mAW -1 and 8.0 × 10 12 Jones, respectively. Moreover, the external quantum efficiency (EQE) was 9.64% at 62.5 mW.cm −2 and 400 nm. Hence, the fabricated photodetector (PD) has a very high photoelectrical response due to hot electrons from the TiN layer, which makes it very hopeful as a broadband photodetector.