Type-I interband transition in undoped ZnSe/BeTe type-II quantum wells under high excitation density

• Published in: Semiconductor science and technology Vol. 24; no. 9; pp. 095016 - 095016 (4)
• Main Authors: Ji, Z W, Mino, H, Oto, K, Akimoto, R
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.09.2009; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Quantum wells; Exciton phonon interaction; Interband transitions; Quantum wells; Beryllium tellurides; Photoluminescence; Line widths; Zinc selenides; Carrier density; Photoexcitation; Trion
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/0268-1242/24/9/095016

A spatially direct photoluminescence (PL) spectrum associated with type-I interband transition of a ZnSe layer in undoped ZnSe/BeTe type-II quantum structures was investigated by varying the photo-excitation density. For a sample with a narrower ZnSe layer both PL intensity and linewidth of the trion show a superlinear increase with increasing excitation density in comparison to that with a wider ZnSe layer. The results are explained by the effective increase of the electron concentration and an enhanced dephasing rate of the trion resulting from the electron-trion scattering. The effective increase of the electron concentration in the ZnSe layer is considered to be originating from both the greater transfer rate of the hole into the BeTe layer due to the narrower ZnSe layer and the efficient spatially indirect transition PL of the complex states through the interface. With decreasing excitation density, no indication of any shift in peak energy density was observed indicating that the studied structures are of excellent quality.