Electromotive force generation due to electron and impurity cyclotron resonances in compound semiconductors

Abstract

We report on the resonant-photoelectromagnetic (R-PEM) effect in semiconductor, that is the electromotive force generation associated with electron cyclotron resonance (ECR) and impurity cyclotron resonance (ICR). This can be explained with a model that the carriers excited by the resonant absorption of the radiation induce the DC voltage through the thermomagnetic process. In this study, we have applied this technique to the n-InGaAs thin film and observed the negative voltage peak in addition to the usual positive ICR one. From the temperature variation and the resonant magnetic field dependence of these signals, we have concluded that the negative signal is induced by the ECR absorption. In addition, we have confirmed that the inversion of polarity for these signals originates in the inhomogeneous distribution of conduction electrons inside the film, and electrons localized at a fraction of the sample mainly cause the resonant absorption. Through the detailed observation and analysis of the generated DC voltage, we can investigate the dynamics of hot carriers inhomogeneously excited in the sample by the ECR as well as the ICR. Moreover, if we pay special attention to the polarity of the generated voltage, we can determine the distribution of electrons and impurities inside the film.