Improvement of Electrical Characteristics of 〈Indium‐Tin Oxide/Silicon Oxide/Polycrystalline n‐Si〉 Solar Cells by a KCN Treatment

Abstract

The photovoltage and the fill factor o f (indium-tin oxide (ITO)/silicon oxide/polycrystalline n-Si) junction solar cells are increased b y immersing S i i n a potassium cyanide solution before the deposition o f a n I T 0 film. Measurements o f the temperature dependence o f the dark current-voltage curves show that the mechanism o f the current flow through the S i depletion layer is changed from trap-assisted multistep tunneling t o thermionic-assisted tunneling b y the KCN treatment, indicating a decrease in the density o f the trap states i n the S i depletion layer. Measurements o f the electrode conductance also show that the trap density is greatly reduced b y the KCN treatment. The improvement o f the electrical characteristics is attributed t o the decrease i n the trap density and an increase i n the barrier height i n n-Si caused b y t h e inclusion o f cyanide ions at t h e oxide/Si interface and/or i n t h e silicon oxide layer.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-06-20 to IP

A ballistic electron emission microscopy study of barrier height inhomogeneities introduced in Au/III-V semiconductor Schottky barrier contacts by chemical pretreatments

“…Shifts of the flat-band potential corresponding to barrier height increases are also found for S 2− , Se 2− , Te 2− ions on n-CdS, n-CdSe, n-CdTe and n-InP [23,24]. Kobayashi et al [25] report φ B increases due to CN − ions at the interface of ITO/n-Si contacts. All these results corroborate our assumption that adsorbed ions produce the observed φ B changes.…”

Studies on interface states at ultrathin SiO2/Si(100) interfaces by means of x-ray photoelectron spectroscopy under biases and their passivation by cyanide treatment

“…37 With the cyanide treatment, on the other hand, the dark current density becomes strongly temperaturedependent, indicating that thermal excitation is important for the current flow mechanism. 37 This result shows that the gap states in the Si depletion layer are removed by the cyanide treatment, supporting the penetration of CN Ϫ ions into the Si.…”

Decrease in the leakage current density of Si-based metal–oxide–semiconductor diodes by cyanide treatment

“…It was found in our previous study of poly-Si-based MOS tunneling diodes that with no treatment, the dark current density depends on the temperature only slightly while it becomes strongly temperature dependent after cyanide treatment. 17 Analysis of the result shows that the dark current flow mechanism changes from trap-assisted multistep tunneling 18 to thermal excitation by cyanide treatment, indicating the passivation of trap states in the poly-Si space charge layer. Figure 4 shows the proposed current flow mechanism for the ͗Al/8 nm SiO 2 /poly-Si͘ MOS diodes in the presence of trap states in poly-Si and interface states.…”