Next-generation electrochemical etching for III-nitride semiconductors: Innovations, applications, and beyond

Electrochemical etching (ECE) has become an essential approach for nanostructuring III-nitride semiconductors, offering precise, scalable control over their physical and functional characteristics. Through ECE, bulk materials such as GaN, InN, and InGaN can be engineered into zero-dimensional nanoparticles, one-dimensional nanowires, and two-dimensional porous frameworks. These nanostructures exhibit enhanced optoelectronic behavior, superior charge transport, and increased surface area properties that make them highly effective at photodetection and gas sensing. The incorporation of ECE-fabricated nanowires into device platforms has led to notable gains in light absorption, carrier dynamics, and detection sensitivity. Additionally, the porous nature of etched III-nitrides supports efficient gas adsorption and reactivity, which is critical for selective sensing applications. While ECE excels in tuning porosity and minimizing defects, complementary methods such as chemical and electroless etching offer expanded capabilities for large-area processing. Ongoing challenges such as achieving uniform etching profiles, reproducibility, and effective device integration necessitate further process refinement and design innovation. This review highlights recent advancements in the ECE of III-nitrides, focusing on nanowire fabrication, performance enhancement in optoelectronic and sensing devices, and the broader outlook for next-generation semiconductor technologies.