Contents
xv
12.4.2 STM and AFM Tips in Electrochemical
Nanomanufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454
12.4.3 Nanopipette-Based Methods . . . . . . . . . . . . . . . . . . . . . . 461
12.4.4 Miscellaneous Electrochemical Preparation
Methods of Nanoelectrodes . . . . . . . . . . . . . . . . . . . . . . . 465
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
Part IV High-Voltage Methods of Nanostructure Preparation
13 Preparation of Nanoporous Oxides from Metals
by Electrochemical Anodization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
13.1 Electrochemistry and High-Voltage Processes . . . . . . . . . . . . . . . . 477
13.2 Historical Background: From the Aluminium Industry
to the Nanotechnology Laboratories . . . . . . . . . . . . . . . . . . . . . . . . . 478
13.3 Traditional Laboratory Technique of PAA Preparation . . . . . . . . . 479
13.3.1 Aluminium Samples to Be Anodized . . . . . . . . . . . . . . . 479
13.3.2 Anodizing Cells: Cell Arrangement, Electrodes,
Thermal Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
13.3.3 Common Electrolyte Solutions . . . . . . . . . . . . . . . . . . . . 481
13.3.4 Voltage and Current Density Ranges
Corresponding to the Stages of the Anodization
Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
13.3.5 Porosity and Degree of Ordering . . . . . . . . . . . . . . . . . . . 483
13.3.6 Composition and Structure of PAA . . . . . . . . . . . . . . . . . 485
13.3.7 Removal of the Remaining Metal and the Barrier
Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
13.3.8 Theoretical Approaches, Modelling of PAA
Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
13.4 Patterning Methods in the PAA Preparation Process . . . . . . . . . . . 487
13.4.1 Patterning Methods for Achieving Regular Pore
Formation on Aluminium . . . . . . . . . . . . . . . . . . . . . . . . . 488
13.4.2 Anodized Porous Aluminium as a Pattern
Transfer Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
13.5 Pore Shaping with Modulated Anodization Conditions . . . . . . . . . 490
13.5.1 Pore Branching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490
13.5.2 Monotonous Pore Diameter Variation . . . . . . . . . . . . . . . 491
13.5.3 Periodic Pore Diameter Modulation . . . . . . . . . . . . . . . . 491
13.6 Pursuits Related to the Extension of the Anodizing
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
13.6.1 Anodization of Commercial Aluminium Samples . . . . . 492
13.6.2 Hard Anodization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
13.6.3 Disparity Between the First and Second
Anodization Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
13.6.4 Increase in Anodization Temperature . . . . . . . . . . . . . . . 493
13.6.5 New Components of the Anodization Baths . . . . . . . . . 494
xv
12.4.2 STM and AFM Tips in Electrochemical
Nanomanufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454
12.4.3 Nanopipette-Based Methods . . . . . . . . . . . . . . . . . . . . . . 461
12.4.4 Miscellaneous Electrochemical Preparation
Methods of Nanoelectrodes . . . . . . . . . . . . . . . . . . . . . . . 465
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
Part IV High-Voltage Methods of Nanostructure Preparation
13 Preparation of Nanoporous Oxides from Metals
by Electrochemical Anodization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 477
13.1 Electrochemistry and High-Voltage Processes . . . . . . . . . . . . . . . . 477
13.2 Historical Background: From the Aluminium Industry
to the Nanotechnology Laboratories . . . . . . . . . . . . . . . . . . . . . . . . . 478
13.3 Traditional Laboratory Technique of PAA Preparation . . . . . . . . . 479
13.3.1 Aluminium Samples to Be Anodized . . . . . . . . . . . . . . . 479
13.3.2 Anodizing Cells: Cell Arrangement, Electrodes,
Thermal Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480
13.3.3 Common Electrolyte Solutions . . . . . . . . . . . . . . . . . . . . 481
13.3.4 Voltage and Current Density Ranges
Corresponding to the Stages of the Anodization
Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
13.3.5 Porosity and Degree of Ordering . . . . . . . . . . . . . . . . . . . 483
13.3.6 Composition and Structure of PAA . . . . . . . . . . . . . . . . . 485
13.3.7 Removal of the Remaining Metal and the Barrier
Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
13.3.8 Theoretical Approaches, Modelling of PAA
Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
13.4 Patterning Methods in the PAA Preparation Process . . . . . . . . . . . 487
13.4.1 Patterning Methods for Achieving Regular Pore
Formation on Aluminium . . . . . . . . . . . . . . . . . . . . . . . . . 488
13.4.2 Anodized Porous Aluminium as a Pattern
Transfer Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
13.5 Pore Shaping with Modulated Anodization Conditions . . . . . . . . . 490
13.5.1 Pore Branching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490
13.5.2 Monotonous Pore Diameter Variation . . . . . . . . . . . . . . . 491
13.5.3 Periodic Pore Diameter Modulation . . . . . . . . . . . . . . . . 491
13.6 Pursuits Related to the Extension of the Anodizing
Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
13.6.1 Anodization of Commercial Aluminium Samples . . . . . 492
13.6.2 Hard Anodization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
13.6.3 Disparity Between the First and Second
Anodization Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
13.6.4 Increase in Anodization Temperature . . . . . . . . . . . . . . . 493
13.6.5 New Components of the Anodization Baths . . . . . . . . . 494