Negative differential resistance induced by thermalization of two-dimensional electrons in terahertz quantum-well photodetectors.

Negative differential resistance (NDR) behavior existing in dark current-voltage (IV) curves of terahertz quantum-well photodetectors (QWPs) is theoretically investigated. Due to electron-electron scattering, the localized two-dimensional (2D) electrons in terahertz QWPs are thermalized. In steady state, the effective temperature of the 2D electrons is found to be higher than that of lattice. A self-consistent model is used to simulate the dark IV curves of terahertz QWPs, taking into account the thermalization effect of the 2D electrons. The NDR behavior is qualitatively reproduced. The periodic structures of electric-field domain and 2D electron occupation are formed in the NDR regime. The improved self-consistent model is useful for further understanding of the electron transport properties and improving the performance of terahertz QWPs. [ABSTRACT FROM AUTHOR]