Title :
Optical absorption, photo-luminescence and miniband formation of a highly ordered and dense 2-dimensional array of Si nanodisks for quantum dot solar cells
Author :
Igarashi, Makoto ; Huang, Chi-Hsien ; Wang, Xuan-Yu ; Budiman, Mohd Fairuz ; Tamura, Yosuke ; Kiba, Takayuki ; Murayama, Akihiro ; Kaizu, Toshiyuki ; Okada, Yoshitaka ; Samukawa, Seiji
Author_Institution :
Inst. of Fluid Sci., Tohoku Univ., Sendai, Japan
Abstract :
We fabricated a highly ordered and dense 2-dimensional array of Si nanodisks (NDs) with our new processes using a bio-template and damage-free neutral beam. Direct-bandgap-like photon emissions were observed from the Si-NDs due to quantum confinement by using time resolved PL measurements. The PL time-profiles were identified in three components (nanosecond region or less) originated in lateral coupling of wave-function i.e. miniband state and localized state in silicon nanodisks. Furthermore, The I-V characteristics of the 2D array of Si-NDs using conductive atomic force microscopy (AFM) indicated that the electronic states of the neighboring NDs were coupled and formed minibands in the 2D array. We also fabricated Si-NDs with an inter-layer of SiC, and found that the SiC matrix could yield a high absorption coefficient without any shift in the bandgap energy (Eg) of the Si-ND structure.
Keywords :
atomic force microscopy; photoluminescence; semiconductor quantum dots; silicon; silicon compounds; solar cells; 2-dimensional array; Si; SiC; absorption coefficient; bandgap energy; biotemplate; conductive atomic force microscopy; damage free neutral beam; direct bandgap like photon emissions; lateral coupling; miniband formation; nanodisks; optical absorption; photoluminescence; quantum confinement; quantum dot solar cells; Absorption; Arrays; Etching; Neodymium; Photonics; Silicon; Silicon carbide;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE
Conference_Location :
Seattle, WA
Print_ISBN :
978-1-4244-9966-3
DOI :
10.1109/PVSC.2011.6186706