Electron dynamics in modulation p-doped InGaAs/GaAs quantum dots

• Published in: The European physical journal. B, Condensed matter physics Vol. 62; no. 1; pp. 65 - 70
• Main Authors: Wen, X. M., Dao, L. V., Hannaford, P., Mokkapati, S., Tan, H. H., Jagadish, C.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.03.2008; Springer; EDP sciences
• Subjects: Complex Systems; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fluid- and Aerodynamics; Mesoscopic and Nanoscale Systems; 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; Physics and Astronomy; Quantum dots; Solid State Physics; 78.67.Hc Quantum dots; 78.47.Cd Time resolved luminescence; Integrated intensity; Gallium arsenides; Quantum dots; Electron interaction; Photoluminescence; Frequency conversion; Electron hole pair; Self-assembled layers; Modulation doping; Spectral line shift; Indium arsenides
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/e2008-00127-8

. We investigate the electron dynamics of p-type modulation doped and undoped InGaAs/GaAs quantum dots using up-conversion photoluminescence at low temperature and room temperature. The rise time of the p-doped sample is significantly shorter than that of the undoped at low temperature. With increasing to room temperature the undoped sample exhibits a decreased rise time whilst that of the doped sample does not change. A relaxation mechanism of electron-hole scattering is proposed in which the doped quantum dots exhibit an enhanced and temperature independent relaxation due to excess built-in holes in the valence band of the quantum dots. In contrast, the rise time of the undoped quantum dots decreases significantly at room temperature due to the large availability of holes in the ground state of the valence band. Furthermore, modulation p-doping results in a shorter lifetime due to the presence of excess defects.