Structural control of Fano resonances in semiconductor heterostructures

✍ Scribed by Walter Pötz

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 320 KB
• Volume: 26
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1999.0767

✦ Synopsis

Structural control of quantum interference in the optical intrasubband absorption spectrum of GaAs/AlGaAs multi-quantum wells is investigated theoretically. Our study shows that pronounced Fano resonances are in general difficult to obtain in quantum well heterostructures, with a presence of distinct Fano resonance features being the exception rather than the rule. Guided by an analogy to Young's double-slit experiment, we design increasingly improved structures to display Fano resonances. Best results are achieved in structures where there is strong overlap between the ground-state wavefunction and scattering states associated with the uncoupled continuum. Alternatively one may use ionization via two or more resonances. In this case, resonances should not be separated by more than 25 meV to give significant effects. Moreover, we show that resonance features may also be induced without potential barriers to a continuum merely via orthogonality between bound and excited states.