실리콘과 탄소 동시 스퍼터링에 의한 실리콘 양자점 초격자 박막 제조 및 특성 분석

서지정보

ㆍ발행기관 : 한국재료학회 ㆍ수록지정보 : 한국재료학회지 / 20권 / 6호
ㆍ저자명 : 김현종, 문지현, 조준식, 박상현, 윤경훈, 송진수, 오병성, 이정철

영어 초록

Silicon quantum dots (Si QDs) in a superlattice for high efficiency tandem solar cells were fabricated by magnetron rf sputtering and their characteristics were investigated. SiC/Si1-xCx superlattices were deposited by co-sputtering of Si and C targets and annealed at 1000˚C for 20 minutes in a nitrogen atmosphere. The Si QDs in Si-rich layers were verified by transmission electron microscopy (TEM) and X-ray diffraction. The size of the QDs was observed to be 3-6 nm through high resolution TEM. Some crystal Si and -SiC peaks were clearly observed in the grazing incident X-ray diffractogram. Raman spectroscopy in the annealed sample showed a sharp peak at 516 cm-1 which is an indication of Si QDs. Based on the Raman shift the size of the QD was estimated to be 4-6 nm. The volume fraction of Si crystals was calculated to be about 33%. The change of the FT-IR absorption spectrum from a Gaussian shape to a Lorentzian shape also confirmed the phase transition from an amorphous phase before annealing to a crystalline phase after annealing. The optical absorption coefficient also decreased, but the optical band gap increased from 1.5 eV to 2.1 eV after annealing. Therefore, it is expected that the optical energy gap of the QDs can be controlled with growth and annealing conditions.

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