Abstract
In this paper we show that two mechanisms of negative differential conductivity (Bragg diffraction and field induced localization) in superlattices (SLs), previously viewed as different, are actually physically equivalent. An experiment is designed to observe the above negative differential conductance (NDC). To suppress competing NDC mechanisms (e.g. Gunn effect) the SL is placed in the collector of a bipolar transistor and the collector current is measured as a function of base collector voltage at constant emitter current. A broad region of NDC is observed above the critical threshold field, corresponding to progressive wavefunction localization. At higher fields features are observed in the collector current superimposed on a rising Fowler-Nordheim background. Calculations demonstrated that they correspond to SL transmission resonances originating from states supported by subsets of the SL of thickness equal to the electron coherence length.
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References
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Capasso, F., Beltram, F., Sivco, D.L., Hutchinson, A.L., Chu, SN.G., Cho, A.Y. (1991). Transport in Superlattices: Observation of Negative Differential Conductance by Field Induced Localization and Its Equivalence with the Esaki-Tsu Mechanism; Scattering Controlled Resonances in Superlattices. In: Chang, L.L., Mendez, E.E., Tejedor, C. (eds) Resonant Tunneling in Semiconductors. NATO ASI Series, vol 277. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-3846-2_35
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DOI: https://doi.org/10.1007/978-1-4615-3846-2_35
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