Carrier-Transport Processes in n.sup.+-GaAs/n.sup.0-GaAs/n.sup.+-GaAs Isotype Heterostructures with a Thin Wide-Gap AlGaAs Barrier

• Published in: Semiconductors (Woodbury, N.Y.) N.Y.), 2020-05, Vol.54 (5), p.529
• Main Authors: Slipchenko, S. O, Podoskin, A. A, Soboleva, O. S, Yuferev, V. S, Golovin, V. S, Gavrina, P. S, Romanovich, D. N
• Format: Article
• Language: English
• Subjects: Analysis; Electric fields; Gallium arsenide; Ionization; Numerical analysis
• ISSN: 1063-7826
• DOI: 10.1134/S1063782620050139

Experimental studies of n.sup.+-GaAs/n.sup.0-GaAs/n.sup.+-GaAs isotype heterostructures with a 100-nm-thick wide-gap N.sup.0-AlGaAs barrier situated in the n.sup.0-GaAs region are carried out. It is shown that the current-voltage characteristic of the structures under study has a negative-differential-resistance (NDR) portion, with the transition to this region occurring with a time delay that may reach tens of nanoseconds. It is found that operation in the NDR region is associated with the onset of impact-ionization process. Numerical analysis in terms of the energy-balance model demonstrated that the transition to the NDR region is associated with the formation of an electric field domain that covers a part of the lightly doped region between the thin wide-gap N.sup.0-AlGaAs barrier and the heavily doped n.sup.+-GaAs layer and with the onset of impact ionization at the interface with the heavily doped n.sup.+-GaAs layer. A comparative analysis of the experimental data and the modeling results showed that, for the current-voltage characteristics of the heterostructures under study to be correctly described, the model should take into account the less pronounced ability of a heterojunction to restrict carrier transport in the barrier layer.