New Opportunities to Use Quantum Dots

**49**

**Chapter 4**

*Anatolii Isaev*

**1. Introduction**

in fundamental and in applied physics.

by a surface trap with a long lifetime [10].

**Abstract**

Quantum Dots CdSe/ZnS as a

Source Array of Entangled States

A quantum dot is a quantum system in classical space with unique characteristics, as

a result of a large quantum limitation. The experimental results of this chapter substantiate the ability of quantum dots to play a key role in purely quantum processes, for example, teleportation of quantum objects, and the generation of macroscopic quantum gravity force and, of course, are a qubit in quantum computing. A quantum dot has the ability to capture (capture) a photo-induced charge carrier by a surface defect of its crystal structure and, thereby, create a second stable long-lived quantum state, which is a necessary requirement for a qubit. This ability puts a quantum dot out of competition with respect to many other quantum objects, like qubits, in terms of the simplicity and cheapness of their continuous generation in standard laboratory conditions. Quantum dots have received wide recognition because of their unique exciton luminescence characteristics; this chapter substantiates a fundamentally new area to use quantum dots in the development and study of both fundamental and applied physics.

**Keywords:** quantum dots, metastable excitons, qubit, quantum entanglement

Semiconductor quantum dots (QDs), for example, CdSe/ZnS is an attractive quantum object in classical space. Attractiveness is based on the unique characteristics of nanoscale structures with a large quantum limitation. The high quantum yield of exciton luminescence (up to 80%), the narrow band of this luminescence, the long photo stability and the rearrangement of the exciton luminescence band in a wide spectrum range, depending on the size of the nanoparticles, have specific unique characteristics of these crystalline nanostructures [1]. These characteristics provide potential applications in photovoltaic and laser devices, thin-film transistors, light-emitting diodes and luminescent labels in biology and medicine [2–6]. In this article, I want to justify no less, but rather more, meaningful applications, both

We are talking about the properties of crystalline structures to have on their surface quantum defects called surface trap states. These surface traps capture photoinduced charge carriers, usually an electron, and delay its recombination for a fairly long time [7–9]. In [10], the exciton luminescence of CdSe/ZnS QDs was recorded in the millisecond time range and its intensity was six orders of magnitude less than the intensity of exciton luminescence immediately after the photo excitation pulse. Such a quantum state with a long existence of an exciton is called a metastable exciton. A metastable exciton is an electron—hole pair, in which an electron is captured
