123rd General Meeting of the KCS

Type Poster Presentation
Area Electrochemistry
Room No. Exhibition Hall 2
Time 4월 18일 (목요일) 11:00~12:30
Code ELEC.P-442
Subject Layer-by-layer growth of CIGS/CdS architecture on Mo substrates by E-ALD
Authors Mukunthan Ramasamy, ChanYong Jung, Yu-Beom Yeon, Chi-Woo Lee*
Department of Advanced Materials Chemistry, Korea University, Korea
Abstract CuInxGa(1-x)Se2 (CIGS) is a chalcopyrite p-type semiconductor compound which are largely known for its explicit properties of highly adjustable bandgap (1.04 eV for CuInSe2 (x = 0) to 1.68 eV for CuGaSe2 (x = 1)), bandgap found at optimum conversion efficiency range (1.4 ∼ 1.5 eV), high absorption coefficient (1×105 cm−1), and the material is highly stable under high energy irradiation. Cadmium sulfide (CdS), an n-type semiconductor compound with the band gap of 2.4 eV, good optical transmittance and low resistivity makes this compound a noble candidate as a buffer layer in thin-film photovoltaic cells. This CIGS-CdS duo offers the highly efficient CIGS thin-film solar cells available in the market today. The electrochemical atomic layer deposition (E-ALD) which is an electrochemical version of the ALD method, is adopted for making the homogeneous layers of Cu-In-Ga-Se and Cd-S semiconductor compounds on Mo substrate. The E-ALD works under the principle of surface limited reactions (SLRs) which is referred to as underpotential deposition (UPD) in the electrochemical process. The UPD process takes place under or less than the Nernst potential; where an atomic layer formed as the result of the free energy formation of a surface compound. The specific UPD potentials were determined by cyclic voltammetry (CV) studies in respect with each electrolyte solutions. Series of alternate cycles of deposits were performed to form the preferred film with precise stoichiometry. The synthesized films were analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and the PEC experiments. The photoelectrochemical (PEC) studies of a photovoltaic (PV) film could reveal the semiconductive nature of the absorber layer and absorber/buffer film architecture in fast basis. The photoelectrochemical behavior of each layer of the device is important to make the PV cell a defect-free during the device making process. This important technique could help the researcher to analyze the stability of the materials against light irradiation and could lead to improving the materials property.
E-mail mukunthanram@gmail.com