Enhanced recombination tunneling in GaAs pn junctions containing low-temperature-grown-GaAs and ErAs layers

• Published in: Applied physics letters 2003-11, Vol.83 (19), p.4035-4037
• Main Authors: Pohl, P., Renner, F. H., Eckardt, M., Schwanhäußer, A., Friedrich, A., Yüksekdag, Ö., Malzer, S., Döhler, G. H., Kiesel, P., Driscoll, D., Hanson, M., Gossard, A. C.
• Format: Article
• Language: English
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.1625108

We report electrical conductivity studies of highly-doped GaAs pn diodes containing a strongly n-doped low-temperature-grown (LT)–GaAs layer and pn junctions containing an approximately one monolayer thick ErAs layer. At room temperature, current densities of 1 kA/cm2 for the n-LT–GaAs samples and 6 kA/cm2 for the ErAs samples at 1 V forward bias have been measured. The I–V characteristics under forward bias for the n-LT–GaAs and ErAs samples exhibit significantly different behavior. At low temperatures, the n-LT–GaAs samples reveal a shoulder in the I–V characteristics, which can be explained by a model taking into account tunneling of carriers into LT midgap states. A similar model was able to explain the current transport in the ErAs diodes as tunneling of carriers into metallic regions inside the pn junction.