P-type transparent oxides for energy application

Abstract

Transparent conducting oxide (TCO) has the advantage of high electrical conductivity and high transparency of light. The most popular TCO used in industry field such as ITO, FTO, ZnO and aluminum doped zinc oxide (AZO) are n-type semiconductor in the natural. The development of p-type TCOs manufacturing is a necessity for various opto-electronic devices application [1]. p-type Cu-based delafossite family attract attention since the first synthesis of CuAlO2 thin films by Kawazoe in 1997 [2]. The CuAlO2 attracts researchers attention due to its highly transparent properties in the visible region, its wide bandgap semiconductor and p-type conduction but the treatment temperature to synthesize well-crystallized CuAlO2 is above 1000°C, therefore the use of expansive substrates such as sapphire, etc.

P-type Cu- based family have the structure CuMO2 where( M) is trivalent cation can be ( Al, Cr, Ga, and Fe) have attracted researcher interest due to their use in various application such as light-emitting diodes [3], battery fabrication [4, 5, 6], transparent diodes and solar cells manufacturing [7, 8].

This Cu- based oxide family shows multi-energy bandgap Eg behaviors in the range 1.1 eV to 3.6 eV [9]. Additional advantages for manufacturing these oxides are that the main composite materials such as Cu and Fe are non-expansive, have relative abundance and are non-toxic.

The delafossite is a copper iron oxide mineral which named in honor of the French crystallographer Gabriel Delafosse, while the CuFeO2 formula was first reported in 1873 by Charles Friedel [10]. Pabst et al. reported the first crystal growth of delafossite in 1935 by solid state synthesis [11].