Accession Number : AD1034763

Title :   InAs Band-Edge Exciton Fine Structure

Descriptive Note : Technical Report

Corporate Author : MIT Lincoln Laboratory Lexington United States

Personal Author(s) : Bischof,Thomas ; Sandoval,Oscar ; Harris,Daniel ; Franke,Daniel ; Grein,Matt ; Wilson,Ryan ; Dauler,Eric ; Steinbrecher,Greg ; Coropceanu,Igor

Full Text :

Report Date : 29 Jul 2015

Pagination or Media Count : 8

Abstract : Semiconductor nanocrystals rarely, if ever, exhibit emission linewidths which are lifetime-limited. Instead, there are a number of linewidth broadening mechanisms which are relevant under various conditions, such as spectral diffusion, charging, and excitonic fine structure. While spectral diffusion and charging are most likely photoinduced effects and thus can be modulated by the excitation rate of the nanocrystals, fine-structure broadening is fundamental to the photophysics of nanocrystals and most likely unavoidable. A complete understanding of the excitonic energy landscape enables us to determine dephasing rates, linewidths, lifetimes, and other parameters essential to optical applications. Here we discuss the relationship between the excitonicfine structure and the emission dynamics of InAs/CdS core/shell nanocrystals. At room temperature wefind steady-state emission dynamics on order of 150 ns, and as the temperature is lowered wefind that the relaxation is greatly slowed (1:9 s at 3:6K). Wefind that these emission dynamics are well-explained by a band-edge model including a pair of dark and bright excitonic states, separated in energy by 2:3 meV.

Descriptors :   semiconductors , excitons , nanocrystals , indium arsenides , excitation , room temperature , steady state

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE