Chirped Bloch oscillations in strain-balanced InGaAs/InGaAs superlattices

✍ Scribed by M. Först; G.C. Cho; T. Dekorsy; H. Kurz

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 174 KB
• Volume: 26
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1999.0762

✦ Synopsis

Bloch oscillations excited in a strain-balanced In x Ga 1-x As/In y Ga 1-y As superlattice by fs optical pulses at 1.55 µm are investigated in time-resolved transmission spectroscopy. The transition from the coherent oscillatory motion to an incoherent drift transport of the electrons is observed via a transient frequency shift of the Bloch oscillations due to the associated screening of the applied electric field. These electric field changes are analyzed quantitatively as a function of the initial field strengths and excitation densities. The incoherent transport can be described by a drift-diffusion model. As a result, the carrier mobility in the superlattice is obtained on a picosecond timescale.