Scattering mechanisms and warm electrons associated with vertical transport in GAAS/ALAS superlattices

✍ Scribed by B. Goutiers; F. Aristone; E. Ranz; F. Mollot

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 213 KB
• Volume: 17
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1995.1026

✦ Synopsis

We have studied the vertical transport properties of short period GaAs/AlAs superlattices (SLs) in the temperature range of (4.2 \mathrm{~K}) up to (300 \mathrm{~K}). We present a discussion of the scattering mechanisms which influence the electronic temperature. A semi-phenomenological formulation of the drift velocity and of the current intensity have been developed, taking into account the warm-electron effect it produces different values of the critical voltages associated with: (i) appearance of instabilities of the current intensity and, (ii) the voltage associated to the drift velocity maximum. Experimental evidence of this separation has been reported. Our results have been compared with analytical expressions. We have shown that the scattering is dominated by roughness for temperatures in the range of (T_{0}=4.2 \mathrm{~K}) up to (T_{0}=200 \mathrm{~K}) typically. For higher temperatures, optical phonon scattering is comparably strong. Scattering processes involving atypical optical phonons are significant for explaning the decrease of the total scattering time in the temperature range of (50 \mathrm{~K}) to (150 \mathrm{~K}), and it cannot be completely neglected at room temperature.