NQPI NanoForum presents Venkata R. Thota on “Time Resolved Photoluminescence Measurements of On-Set and Off-Set of Optically Generated Electric Field in InAs/GaAs Quantum Dot Molecules” on Tuesday, Dec. 2, at 4 p.m. at Clippinger 259.
Ramana Thota
His adviser is Dr. Eric Stinaff, Professor of Physics. NanoForums are presented several times per semester and are sponsored by Nanoscale and Quantum Phenomena Institute.
Abstract: Semiconductor nanostructure devices have attracted a lot of attention due to their unique optical and electrical properties and their ease of incorporation into the existing devices. One of the categories is Quantum Dot Molecules (QDMs); where the confinement plays a key role and the interaction between the charge carriers Charge carriers in QDMs provide a mechanism to control the quantum mechanical features through the application of electric field. Due to the advanced growth mechanisms, where the growth can be monitored down to the single monolayer level, samples of very high quality and almost free of impurities were grown. We made optical measurements on In1-xGaxAs QDMs, grown by using molecular beam epitaxy (MBE), by exciting with Ti:Sapphire Laser whose wavelength can be tuned in the near infrared region and simultaneously applying the electric field along the growth direction. The optical emission spectra showed both Intra (same dot) and inter (different dot) transitions. By exciting high above the wetting layer (EExcitation > 1.22 eV), this inter dot or indirect line has shown a shift (~ 3.24 kV/cm) in the optical emission spectra. This indirect line is used as a sensitive probe to measure the in-built optical generated field. In this presentation, I’ll discuss about the on-set as well as the off-set of this locally created field as a function of excitation energy using Time-Resolved Photoluminescence experiments.
This will be the last Nanoforum of the Fall Semester. Please look for more Nanoforums beginning in January 2015.
Comments