Transient photoluminescence from semiconductor

nanodumbbells

Mikhail Yu. Leonov, Anvar S. Baimuratov,

Alexander V. Baranov, Anatoly V. Fedorov

Department of Optical Physics and Modern Natural Science National Research University of Information Technologies,

Mechanics and Optics Saint Petersburg, Russia

m.yu.leonov@gmail.com

Abstract- We developed the theory of time-resolved

secondary emission from semiconductor nanodumbbells. We

reveal conditions that the signal of secondary emission is

described by a simple formula regardless of the pulse shape. This

formula may prove useful for studying the dephasing and

relaxation parameters of the nanodumbbell electronic subsystem.

Keywords- time-resolved secondary emlsswn; energy

relaxation rates; semiconductor nanodumbbells

I. INTRODUCTION

An important frontier in photonics research and technology is the creation of complex nanostructures [1] from metal, semiconductor, or metal-semiconductor nanoparticles of different shapes. Nonspherical semiconductor nanoparticles, whose shapes range from nanorods [2] and nanoplatelets [3] to tetrapods [4] and tetrahedrons, are often strongly optically anisotropic. The multiple degrees of freedom in the nanostructure design associated with the geometric and composition parameters of their building blocks offer broad opportunities for manipulation of the nanostructure's optical properties and significantly extend the scope of their application [5]. Of particular interest, owing to their inherently strong optical anisotropy, are nanodumbbells [6] made of two quantum dots that are connected by a quantum rod. Despite the many advantages of using nanodumbbells in photonics devices, their physical properties and electronic dynamics are still not fully understood. The cognizance of these features may be achieved via the analysis of the nanodumbbell's optical response measured using the transient secondary emission spectroscopy.

II. RESULTS

This work is devoted to the development of theory of the non stationary anisotropic optical spectroscopy of single semiconductor nanodumbbells of different shapes, and fills the corresponding gap in physics of low-dimensional systems.

The authors gratefully acknowledge the financial support of this work from the Ministry of Education and Science of the Russian Federation (Grant No. 14.B25.31.0002) and the Russian Foundation for Basic Research (Grants No. 12-02-01263 and No. 12-02-00938). The Ministry of Education and Science of the Russian Federation also supports M.Yu.L. and A.S.B., through its scholarships of the President of the Russian Federation for young scientists and graduate students (2013-2015). The work of I.D.R. is sponsored by the Australian Research Council, through its Discovery Early Career Researcher Award DE120100055.

Ivan D. Rukhlenko

Advanced Computing and Simulation Laboratory, Department of Electrical and Computer System

Engineering, Faculty of Engineering Monash University Clayton, Australia

Using the density matrix formalism, we develop a uniform theory of time-resolved secondary emISSion from a semiconductor nanodumbbells, which are resonantly excited by a sufficiently broad laser pulse. We reveal the conditions under which the signal of secondary emission is described by a fairly simple formula regardless of the pulse's shape. Furthermore, we show that the transient secondary emission spectroscopy allows one to reliably determine the energy relaxation rates of the nanodumbbell's electronic states.

III. CONCLUSION

The derived analytical expressions for the signal of secondary emission can be used for studying the dynamics of quantum transitions in semiconductor nanodumbbells, whereas the novel approaches for the determination of energy relaxation rates suggested in our work may prove useful for developing advanced optical methods of nondestructive analysis of relaxation processes in quantum nanostructures.

REFERENCES

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