Energetics and carrier transport in doped Si/SiO2 quantum dots

Abstract

In the present theoretical work we have considered impurities, either boron or phosphorous, located at different substitutional sites in silicon quantum dots (Si-QDs) with diameters around 1.5\,nm, embedded in a SiO2 matrix. Formation energy calculations reveal that the most energetically-favored doping sites are inside the QD and at the Si/SiO2 interface for P and B impurities, respectively. Furthermore, electron and hole transport calculations show in all the cases a strong reduction of the minimum voltage threshold, and a corresponding increase of the total current in the low-voltage regime. At higher voltage, our findings indicate a significant increase of transport only for P-doped Si-QDs, while the electrical response of B-doped ones does not stray from the undoped case. These findings are of support for the employment of doped Si-QDs in a wide range of applications, such as Si-based photonics or photovoltaic solar cells.

References in corpus (10)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Selfconsistent order-N density-functional calculations for very large systems
• Electron correlation resonances in the transport through a single quantum level
• Size, oxidation, and strain in small Si/SiO2 nanocrystals
• Preferential positioning of dopants and co-dopants in embedded and freestanding Si nanocrystals
• Silicon Nanocrystallites in SiO2 Matrix: The Role of Disorder and Size
• Excitons in Silicon Nanocrystalites: The Nature of Luminescence
• Doping of Si nanoparticles: the effect of oxidation
• Decoupling and antiresonance in electronic transport through a quantum dot chain embodied in an Aharonov-Bohm interferometer

Cited by in corpus (2)

• Doped and Codoped Silicon Nanocrystals: the Role of Surfaces and Interfaces
• Excitation transport in quantum devices: analytical time-dependent non-equilibrium green function algorithm