Quantum dot blinking: relevance to physical limits for nanoscale optoelectronic device

Abstract

In designing nanoscale optoelectronic devices based on a small number of active quantum dots, it is of interest to consider that semiconductor nanocrystals (quantum dots) are observed to blink "on" and "off". The time probability distributions scale as an inverse power law for colloidal quantum dots and exponentially for self-assembled dots. Possible mechanisms that cause the inverse power law and exponential blinking statistics are discussed in the paper and the relevance to quantum-dot based system architectures is discussed.

Anomalous enhanced emission from PbS quantum dots on a photonic-crystal microcavity

“…8). In fact, they all show sublinear behavior, which fits very well to a power law dependence of the form y ¼ ax b , with b ¼ 0:75 for the E x 1 resonance at room temperature and b ¼ 0:82 for the E y 2 resonance at 105 K. This sublinear behavior [54] is commonly observed in colloidal QD PL and is believed to be associated with quenching processes [55]. Second, the ratio between each emission peak and the background remains constant to within <20% over the same 3 orders of magnitude change in excitation intensities, indicating that there is no spectral redistribution upon change in pump intensity.…”

Efficient multi-exciton emission from quantum dots.

“…In fact, they all show sub-linear behavior which can fit to a power law dependence of y=ax b very well; with b=0.73 for the E x 1 resonance at room temperature and b=0.78 for the E y 2 resonance at 105K. This sub-linear behavior [50] is commonly observed in colloidal quantum dots photoluminescence and is believed to be associated with the quantum dot blinking problem where quantum dot can be charged or carriers are trapped on the surface [51]. Second, the ratio between each emission peak and the background remains constant to within <20% over the same 3 orders of magnitude change excitation intensities, there is no spectral redistribution upon change in pump intensity.…”