Tuning Optoelectronic Properties of Double Quantum Dot Structure Using Tight-Binding Model for Photo-Electric Applications

Abstract

In electronics field, researchers and industries have been working to fabricate low-cost optoelectronic devices by using less materials in the fabrication process. Thus, miniaturization concept has been used in the design and synthesis of the fabricated materials and devices based on nano-dimension. However, reducing the used materials would affects the overall performance of the devices and new building blocks materials are needed to pass the performance capacity limits of current silicon-based materials. Quantum Dots DQs have been introduced and attracted much attention among researchers because of their unique characteristics that are necessary for many potential applications by using nano-dimensions structures. These properties include size-tunable optical and other electronic characteristics that are not found in the current bulk materials. Although there has been interested QDs experimental studied that have been already carried out, different theoretical efforts must be introduced in order to provide good understanding of the possible and different QDs applications. In this work, therefore, optoelectronic properties of Double Quantum Dots DQDs system were studied theoretically to provide important information about the possibility of using this system in photoelectric applications. A tight-binding framework was adopted to describe the system, and all the calculations were carried out based on the steady state formalism. The proposed DQD structure was connected to metallic leads and studied to investigate the QD size dependent. The transmission calculation presented first through the electron transport mechanism. Tunneling current and conductance were then presented to provide general understanding about the behavior of the proposed system. A correlation of transmission, current and conductance results with QD radius R, incident photon energy Eph, Temperature and bias voltage have been identified. Therefore, this correlation is strongly supporting the proposal of using DQD system in fabricating nanoscale photovoltaic devices, particularly, solar cells.