Sequential tunneling in doped superlattices: Fingerprints of impurity bands and photon-assisted tunneling

Article

关键词: ELECTRIC-FIELD DOMAINS;    SEMICONDUCTOR SUPERLATTICES;    QUANTUM-WELLS;    TRANSPORT;    MODEL;    POLARIZABILITY;    SPECTROSCOPY;    LOCALIZATION;    OSCILLATIONS;    CONDUCTANCE;   

DOI  :  10.1103/PhysRevB.56.13268

来源: SCIE

【 摘 要 】

We report a combined theoretical and experimental study of electrical transport in weakly coupled doped superlattices. Our calculations exhibit negative differential conductivity at sufficiently high electric fields for all dopings. In low-doped samples the presence of impurity bands modifies the current-voltage characteristics substantially, and we find two different current peaks whose relative height changes with the electron temperature. These findings can explain the observation of different peaks in the current-voltage characteristics with and without external THz irradiation in low-doped samples. From our microscopic transport model we obtain quantitative agreement with the experimental current-voltage characteristics without using any fitting parameters. Both our experimental data and our theory show that absolute negative conductance persists over a wide range of frequencies of the free-electron laser source.

【 授权许可】

Free