Characterizing defects in p–n junctions: an analysis of admittance spectroscopy

Abstract Admittance spectroscopy (AS) is a well-established non-destructive electrical characterization technique, characterized by its rapid response times, high accuracy, and independence from stringent rectification characteristics. Despite its potential as a powerful tool for defect analysis and performance evaluation in semiconductor devices, particularly those with p–n junction structures, existing research remains insufficiently in-depth. Defect analysis issues in various p–n junction-based devices are investigated in this paper, including solar cells, light-emitting diodes, and laser diodes. The principles and features of AS are systematically compared with those of deep-level transient spectroscopy. Several case studies on defect analysis and device performance evaluation are presented, providing researchers with a rapid understanding of the methodology. Additionally, common characterization challenges, such as carrier freezing, the extraction of carrier mobility, and negative capacitance, are addressed in detail, with strategies for analyzing these phenomena using AS. This tutorial aims to elucidate the mechanisms underlying defects in p–n junctions and provide guidance for device performance analysis.