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Journal of the Korean Ceramic Society 2000;37(3): 219. |
Spin-coating에 의한 $Ge_{20}As_{20}Se_{60}$ 비정질 chalcogenide 박막의 제조 및 광특성 분석 |
이강구, 최세영1 |
연세대학교 재료공학과 1연세대학교 재료공학부 |
Preparation and Characterization of $Ge_{20}As_{20}Se_{60}$ Amorphous Chalcogenide Thin Film by Spin Coating |
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ABSTRACT |
Amorphous Ge20As20Se60 chalcogenide thin films were prepared by spin coating technique from mixed solutions of As40Se60 and Ge40Se60 dissolved in ethylenediamine. Films were prepared at a roating speed of 3500 rpm and spinning time was 10 second and heat-treateed at 27$0^{circ}C$ for 1 hour. The resulting film thickness and RMS roughness were approximately 340 nm and 15$AA$. Photostructure changes were investigated with 514.5nm Ar+ laser irradiation and heat-treatment. After Ar+ laser irradiation, transmittance and transmission efficiency decreased respectively up to 24.9% at 2.43 eV and 67.5% at 3.27 eV, and absorption edge shifted toward long wavelength. Optical bandgap changed from 2.03 to 1.83 eV, and absoprtion coefficient and absorption efficiency increased up to 0.33$times$105cm-1 at 3.37eV and 88.3% at 1.31 eV, respectively. These photodarkening state were recovered reversibly by heat-treatment at 27$0^{circ}C$ for 1 hour. Photodarkening and thermal bleaching effects by laser irradiation and heat-treatment revealed reversible amorphous-to-amorphous transition varying only coordination number. |
Key words:
Amorphous $Ge_{20}As_{20}Se_{60}$ chalcogenide thin film, Spin coating, Photostructural changes, Photodarkening, Thermal bleaching |
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