Laser interference lithography-defined electrochemical etching of ordered InP nanopore arrays

To address the challenge of disordered crysto-oriented pore (COP) formation during organized porous InP growth, we demonstrate a strategy based on laser interference lithography-defined electrochemical etching to achieve intact porous InP structures. Simulation studies reveal that the electric field increases monotonically as the pore-opening diameters decrease (from 1 μm to 0.4 μm at a constant period of 2 µm) and as the period lengths decrease (from 5 μm to 0.2 μm with a 1 : 1 duty ratio), under a constant current density of 320 mA cm^-2. Experiments confirm that the COP layer thickness decreases with reduced pore-opening diameters and periods at the same current density, ultimately vanishing at a period of approximately 0.4 μm (1 : 1 duty ratio). These results indicates that COP layers can be eliminated while the pore-opening dimensions approach certain critical values, providing a new approach for fabricating defect-free porous InP structures via laser interference lithography-defined electrochemical etching.