Generation and Tuning of Semiconductor Electronic and Functional Properties through Electrochemical Patterning.

This Account presents surface electrochemical nanopatterning as a powerful and underexplored strategy for engineering the electronic and functional properties of electrochemically active materials. By enabling precise, localized manipulation of electronic states at the micro- and nanoscale, this technique offers a unique pathway to unlock and control intrinsic material properties. These capabilities open new frontiers in materials science, with implications ranging from catalysis to the fabrication of advanced, multifunctional devices. Traditional lithographic techniques, such as photolithography, electron beam lithography, and nanoimprinting, mainly focus on shaping surface topography. In contrast, electrochemical nanopatterning introduces a fundamentally different approach: it modifies the material itself. By changing oxidation states, creating or healing defects, and tuning surface chemistry, this method allows for direct control of material properties. Consequently, it greatly expands the range of applications, enabling the development of materials with customized electronic and functional features. This Account focuses specifically on stamp-assisted electrochemical lithography (ECL), a versatile and scalable technique. We start by outlining the fundamental principles of ECL, including the electrochemical processes that drive it, namely oxidation, reduction, and defect generation. Next, we trace its historical development and highlight its advantages over traditional nanofabrication methods, particularly in terms of simplicity, cost-effectiveness, and compatibility with a wide range of materials. Through a curated selection of case studies, we demonstrate how ECL can be used to (i) generate and tune electronic properties, (ii) impart various functional behaviors, and (iii) achieve spatially controlled defect engineering, especially in semiconductors. Crucially, the ability to fabricate large-area samples has allowed us to harness size-dependent properties that were previously inaccessible in electrochemical nanolithography performed via scanning probe techniques, such e catalysis and the in situ fabrication of nanoclusters. These findings dramatically expand the scientific and technological potential of ECL, opening new avenues for innovation and application. The example cases were selected for their relevance to current challenges in materials science and emerging technologies. Notable applications include in situ healing in resistive switching devices, the development of critical-element-free catalysts, and the direct fabrication of active components within devices. Many of these studies were pioneering at the time of publication and have only recently gained broader recognition due to the growing interest in sustainable, low-cost, and scalable nanofabrication techniques. We emphasize ECL's unique capabilities in enabling regenerable resistive switching, spatially selective nanoembedding of functional nanoparticles, and creating functional surface patterns. These features position ECL as a promising tool for bridging the gap between fundamental research and practical device integration. Moreover, the method's compatibility with ambient conditions and its potential for large-area processing make it particularly attractive for industrial applications. In the final section, we discuss the frontier and the perspectives of ECL. We propose strategies to enhance resolution, reproducibility, and integration with existing manufacturing platforms. We also outline future directions, including the development of hybrid patterning approaches. Looking ahead, we envision ECL playing a central role in the development of next-generation materials and devices, particularly in fields where precise control over local properties is essential for both performance and functionality.