Modulation spectroscopy on metamorphic InAs quantum dots

✍ Scribed by E.Y. Lin; C.Y. Chen; T.E. Tzeng; S.L. Chen; David J.Y. Feng; T.S. Lay

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 878 KB
• Volume: 42
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/j.physe.2010.04.005

✦ Synopsis

The modulation spectroscopy on 1.45 mm metamorphic InAs quantum dots (QDs) with In 0.3 Ga 0.7 As capping layer grown on GaAs substrate by molecular beam epitaxy (MBE) has been investigated by differential absorption (Da), electro-reflectance (ER), and photo-reflectance (PR) spectra at different reverse bias. The optical transitions of the ground state, excited states, and wetting layers were identified and discussed. The micro-structure characterization was also analyzed by TEM and AFM. The variation of refractive index spectra (Dn) by calculating Da spectra through Kramers-Kronig transform is obtained to study the electro-absorption behaviors. Additionally, a simple physical model is proposed to explain the experimental values between the Dn and DR spectra performed by two different modulation spectroscopies (Da and ER). The built-in electric field of metamorphic InAs QDs structure was determined to analyze the Franz-Keldysh Oscillation (FKO) extreme in PR spectra with different bias.