AVS 51st International Symposium
    Semiconductors Tuesday Sessions
       Session SC-TuA

Paper SC-TuA5
Tuning of the Emission Wavelength of Self-assembled InAs/InP (001) Quantum Dots using Grown-in Defects and Ion Implantation

Tuesday, November 16, 2004, 2:40 pm, Room 304C

Session: Semiconductor Heteroepitaxy and Nanostructures
Presenter: C. Dion, École Polytechnique de Montréal, Canada
Authors: C. Dion, École Polytechnique de Montréal, Canada
N. Shtinkov, École Polytechnique de Montréal, Canada
S. Raymond, Conseil National de Recherche du Canada, Canada
M. Chicoine, Université de Montréal, Canada
F. Schiettekatte, Université de Montréal, Canada
P.J. Poole, Conseil National de Recherche du Canada, Canada
R.A. Masut, École Polytechnique de Montréal, Canada
P. Desjardins, École Polytechnique de Montréal, Canada
Correspondent: Click to Email
We have investigated the effect of post-growth rapid thermal annealing (RTA), grown-in defects, and ion implantation on the low temperature photoluminescence (PL) spectra of self-assembled InAs/InP(001) quantum dots (QD) grown by chemical beam epitaxy (CBE) and metal-organic vapor phase epitaxy (MOVPE) in order to develop a detailed understanding of the key diffusion mechanisms involved in such defect-mediated intermixing techniques. In untreated samples, blueshifts of up to 90 meV in the PL spectra are observed after RTA at 800 °C for 210s with no broadening of the emission peak. We attribute this thermally induced shift to the diffusion of group V atoms between the QD and the surrounding material. In order to promote interdiffusion and to obtain larger blueshifts, we have studied the effect of introducing point defects into an InP capping layer, far from the QD region, either by growing InP at low temperature or by implanting P atoms at doses ranging from 10@super11@ to 10@super 14@ ion/cm@super 2@. The introduction of grown-in defects results in a marked increased in PL shifts, which can reach up to 250 meV following RTA at 765 °C for 90 s, revealing that the excess of points defects in that layer promote interdiffusion in the QD region. Even more dramatic effects are measured in ion implanted sample for which significant blueshifts of 300 meV can be observed following anneals at temperatures as low as 400 °C. In order to quantify these effects, we carried out tight-binding calculations of the transition energies in thin diffused quantum wells. Experimental results for the emission of the wetting layer and our simulations indicate that ion implantation leads to an important reduction of the activation energy for As/P interdiffusion to values as small as 0.4 ± 0.2 eV.