Improvement of 〈indium-tin-oxide/silicon oxide/n-Si〉 junction solar cell characteristics by cyanide treatment

Abstract

The performance of 〈indium-tin-oxide (ITO)/silicon oxide/n-Si(100)〉 junction solar cells is improved by immersing Si wafers in a potassium cyanide solution before the ITO deposition. It is found from x-ray photoelectron spectroscopy measurements that about 3% monolayer cyanide (CN−) ions are present on the Si surface after the cyanide treatment. The temperature dependence of the current–voltage curves shows that the band bending in n-Si is increased by the cyanide treatment. The increase in the band bending is attributed to an upward Si band edge shift caused by the presence of CN− ions at the oxide/Si interface and/or in the oxide layer. Conductance–voltage measurements show that the density of trap states considerably decreases after the cyanide treatment. The conductance decrease is attributed to the passivation of interface states by the adsorption of CN− ions on Si dangling bonds.

On the topographic and optical properties of SiC/SiO2 surfaces

“…AFM measurements were performed in a tapping mode with a KEYENCE VN-800 microscope. The a-SiC:H samples were cleaned by the RCA method, etched with diluted HF (10%), oxidized by the NAOS method, annealed in forming gas and passivated by the CN method [11]. Various oxidation and passivation conditions were used to obtain SiO 2 layers with different properties as can be seen in Tab.…”

“…In the present study the hydrogen plasma treatment passivation was applied to the 3C SiC and 4H SiC surfaces. The a-SiC:H/SiO 2 layers formed by the NAOS method were passivated by a cyanide treatment under various experimental conditions [11][12][13][14]. We studied changes of the surface roughness during these oxidation and passivation procedures and measured surface properties were used for the optical parameter determination.…”

Room-temperature synthesis of epitaxial oxide thin films for development of unequilibrium structure and novel electronic functionalization

“…The epitaxial ITO films were obtained at relatively high temperatures over 400°C on the single-crystalline oxide substrates such as yttria-stabilized zirconia (YSZ) to get the highly electrically conductive ITO films. 19) On the other hand, heteroepitaxial growth of oxide thin films on silicon substrates has attracted much interest, since it has applicability to the silicon-on-insulator (SOI) structure and the buffer layers in oxide electronics. 20) CeO 2 is an ideal buffer layer for fabricating epitaxially grown functional oxides on silicon substrates because of its chemical stability and excellent lattice match with silicon (misfit factor: ³0.35%), as reported previously.…”

Passivation of defect states in surface and edge regions on pn-junction Si solar cells by use of hydrogen cyanide solutions

“…Several defect passivation methods applicable to Si materials have been developed, e.g., hydrogen plasma treatment [1,2], forming gas annealing [3,4], deposition of a hydrogen-containing silicon nitride layer [4,5], wet-chemical passivation [6], etc. We have also developed a method of defect passivation for semiconductor devices called cyanide method [7][8][9][10][11][12][13] which can simultaneously remove metal contaminants [14][15][16][17][18][19]. The cyanide method simply includes immersion of Si materials in di-lute cyanide solutions such as HCN aqueous solutions at room temperature.…”