In situ growth of oriented (AlxGa1-x)2O3 nanorod arrays on FTO glass substrates through forced hydrolysis

Large-area, high-density, and directionally arranged (Al x Ga 1- x ) 2 O 3 nanorod arrays were successfully synthesized in situ on FTO glass substrates via a simple hydrothermal method using Ga(NO 3 ) 3 and Al(NO 3 ) 3 mixed aqueous solution as precursor. Compared to powder samples, the thin-film samples exhibited a stronger preferred orientation, with the nanorod arrays growing preferentially along the [110] direction. The formation mechanism of the oriented nanorod arrays is proposed according to the model of liquid phase heterogeneous nucleation and anisotropic crystal growth. As the Al composition increased, the crystallite size decreased, the specific surface area increased, and the optical band gap widened. This study presents a promising candidate for further gas sensor application.