Effects of formation of mini-bands in two-dimensional array of silicon nanodisks with SiC interlayer for quantum dot solar cells

• Published in: Nanotechnology Vol. 24; no. 1; p. 015301
• Main Authors: Igarashi, Makoto, Budiman, Mohd Fairuz, Pan, Wugen, Hu, Weiguo, Tamura, Yosuke, Syazwan, Mohd Erman, Usami, Noritaka, Samukawa, Seiji
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 11.01.2013; Institute of Physics
• Subjects: Applied sciences; Arrays; Cross-disciplinary physics: materials science; rheology; Electronics; Energy; Etching; Exact sciences and technology; Interlayers; Joining; Materials science; Methods of nanofabrication; Molecular electronics, nanoelectronics; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Natural energy; Photovoltaic conversion; Physics; Quantum dots; Qunatum dots; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon carbide; Solar cells. Photoelectrochemical cells; Solar energy; Two dimensional; Wavefunctions; Solar cells; Interlayers; Atomic force microscopy; Electrical conductivity; High density; Quantum dots; Digital simulation; Template reaction; Etching; Absorption coefficients; Electrical measurement; Experimental result; Charge carrier generation; Wave functions; Silicon; Absorption spectra; Damage; Arrays; Nanostructured materials; Optical absorption; Nanomaterial synthesis
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/24/1/015301

A sub-10 nm, high-density, periodic silicon nanodisk (Si-ND) array with a SiC interlayer has been fabricated using a new top-down process that involves a 2D array of a bio-template etching mask and damage-free neutral beam etching. Optical and electrical measurements were carried out to clarify the formation of mini-bands due to wavefunction coupling. We found that the SiC interlayer could enhance the optical absorption coefficient in the layer of Si-NDs due to the stronger coupling of wavefunctions. Theoretical simulation also indicated that wavefunction coupling was effectively enhanced in Si-NDs with a SiC interlayer, which precisely matched the experimental results. Furthermore, the I-V properties of a 2D array of Si-NDs with a SiC interlayer were studied through conductive AFM measurements, which indicated conductivity in the structure was enhanced by strong lateral electronic coupling between neighboring Si-NDs. We confirmed carrier generation and less current degradation in the structure due to high photon absorption and conductivity by inserting the Si-NDs into p-i-n solar cells.