Characterization of semiconductor interfaces by second-harmonic generation

In recent years, optical second-harmonic generation has matured into a versatile and powerful technique for probing the electronic and structural properties of buried solid–solid interfaces. In particular Si/SiO2 interfaces have been studied extensively and significant progress has been made in understanding the sensitivity of second-harmonic generation to interface defects, steps, strain, roughness, electric fields, carrier dynamics, and chemical modifications. The macroscopic and microscopic aspects of the second-order nonlinear optical effects at buried semiconductor interfaces have been treated theoretically by first-principles calculations and semi-empirical models. It is the aim of this review article to present a comprehensive overview of recent accomplishments, current understandings and future directions in this field.