Method for preparing anodic aluminum oxide-based photonic crystal product and anodic aluminum oxide-based photonic crystal product prepared thereby

An anodic aluminum oxide-based photonic crystal product, comprising:

• an aluminum-containing object;
• an N number of first porous aluminum oxide films that are sequentially stacked on a surface of the aluminum-containing object along a first direction, the first direction being defined as a direction from a topmost one of the first porous aluminum oxide films, which is distal from the aluminum-containing object, to a bottommost one of the first porous aluminum oxide films, which is proximal to the aluminum-containing object, each of the first porous aluminum oxide films including a plurality of first nanopore structures which extend along the first direction and which are spaced apart from one another along a second direction that is perpendicular to the first direction;
• and
• a second porous aluminum oxide film formed on the surface of the aluminum-containing object and beneath an Nth first porous aluminum oxide film among the N number of first porous aluminum oxide films in the first direction, the second porous aluminum oxide film including a plurality of second nanopore structures which extend along the first direction and which are spaced apart from one another along the second direction,
• wherein each of the plurality of second nanopore structures has a cross-section of a tubular shape in the first direction, and includes an upper porous section and a lower porous section, the upper porous section being is distal from the aluminum-containing object, widens at a top part, and being in spatial communication with a corresponding one of the plurality of the first nanopore structures of the Nth first porous aluminum oxide film, the lower porous section being proximal to the aluminum-containing object and being in spatial communication with the upper porous section and the surface of the aluminum-containing object,
• wherein a thickness of the second porous aluminum oxide film, which is measured from a top end to a bottom end along the first direction, is greater than a total thickness of the plurality of the first porous aluminum oxide films, and
• wherein the thickness of the second porous aluminum oxide film gradually increases along a third direction that is opposite to the second direction and that is perpendicular to the first direction.