• Transactions on Electrical and Electronic Materials
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• v.14 no.3
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• pp.160-163
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• 2013

We investigated the effect of light intensity and wavelength of a solar cell device by using photoconductive atomic force microscopy (PC-AFM). The $POCl_3$ diffusion doping process was used to produce a p-n junction solar cell device based on a Poly-Si wafer and the electrical properties of prepared solar cells were measured using a solar cell simulator system. The measured open circuit voltage ($V_{oc}$) is 0.59 V and the short circuit current ($I_{sc}$) is 48.5 mA. Also, the values of the fill factors and efficiencies of the devices are 0.7% and approximately 13.6%, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, was used for direct measurements of photoelectric characteristics in local instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics were observed. Results obtained through PC-AFM were compared with the electric/optical characteristics data obtained through a solar simulator. The voltage ($V_{PC-AFM}$) at which the current was 0 A in the I-V characteristic curves increased sharply up to 1.8 $mW/cm^2$, peaking and slowly falling as light intensity increased. Here, $V_{PC-AFM}$ at 1.8 $mW/cm^2$ was 0.29 V, which corresponds to 59% of the average $V_{oc}$ value, as measured with the solar simulator. Also, while light wavelength was increased from 300 nm to 1,100 nm, the external quantum efficiency (EQE) and results from PC-AFM showed similar trends at the macro scale, but returned different results in several sections, indicating the need for detailed analysis and improvement in the future.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.105-110
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• 2011

The doping procedure in crystalline silicon solar cell fabrication usually contains oxygen injection during drive-in process and removal of phosphorous silicate glass(PSG). In this paper, we studied the effect of oxygen injection and PSG on conversion efficiency of solar cell. The mono crystalline silicon wafers with $156{\times}156mm^2$, $200{\mu}m$, $0.5-3.0{\Omega}{\cdot}cm$ and p-type were used. After etching $7{\mu}m$ of the surface to form the pyramidal structure, the P(phosphorous) was injected into silicon wafer using diffusion furnace to make the emitter layer. After then, the silicon nitride was deposited by the PECVD with 80 nm thickness and 2.1 refractive index. The silver and aluminium electrodes for front and back sheet, respectively, were formed by screen-printing method, followed by firing in 400-425-450-550-$880^{\circ}C$ five-zone temperature conditions to make the ohmic contact. Solar cells with four different types were fabricated with/without oxygen injection and PSG removal. Solar cell that injected oxygen during the drive-in process and removed PSG after doping process showed the 17.9 % conversion efficiency which is best in this study. This solar cells showed $35.5mA/cm^2$ of the current density, 632 mV of the open circuit voltage and 79.5 % of the fill factor.

• Korean Journal of Materials Research
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• v.28 no.11
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• pp.680-684
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• 2018

We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A $POCl_3$ diffusion doping process is used to produce a p-n junction solar cell device based on a polySi wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage($V_{oc}$) is 0.59 V and the short circuit current($I_{sc}$) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6 %, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage($V_{PC-AFM}$) at which the current is 0 A in the I-V characteristic curves increases sharply up to $18W/m^2$, peaking and slowly falling as light intensity increases. Here, $V_{PC-AFM}$ at $18W/m^2$ is 0.29 V, which corresponds to 59 % of the average $V_{oc}$ value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.

• New & Renewable Energy
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• v.5 no.1
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• pp.26-31
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• 2009

The surface etching characteristics of single crystalline silicon wafer were investigated using potassium hydroxide (KOH) and tetramethylammonium hydroxide (TMAH). The saw damage layer was removed after 10min by KOH 45wt% solution at $80^{\circ}C$. The wafer etched at high temperature ($90^{\circ}C$) and in low concentration (4wt%) of TMAH solution showed an increased etch rate of silicon wafer and wavy patterns on the surface. Especially, pyramidal textures were formed in 4wt% TMAH solution without alcohol additives.

• Journal of the Semiconductor & Display Technology
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• v.15 no.3
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• pp.6-11
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• 2016

Silicon wafer is one of main materials in solar cell. Micro-cracks in silicon wafer are one of reasons to decrease efficiency of energy transformation. They couldn't be observed by human eye. Also, their shape is not only various but also complicated. Accordingly, their shape classification is absolutely needed for manufacturing process quality and its feedback. The performance of typical classification techniques which is principal component analysis(PCA), neural network, fusion model to integrate PCA with neural network, and support vector machine(SVM), are evaluated using pattern features of micro-cracks. As a result, it has been confirmed that the SVM gives good results in micro-crack classification.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.5
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• pp.38-42
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• 1982

N+-P/P+solar cells were fabricated by using the polycrystalline silline wafer with the resistivity of 3-6 ohm-cm. minority carrier lifetimes, measured by Nd: YAG laser, were from 100ns up to 150ns. Conversion efficiency measured under AM 1 irradiation, were about 4%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1523-1524
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• 2013

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.55-59
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• 2020

Copper Oxide (CuO) films were deposited on the n-type silicon wafer by rf magnetron sputtering for heterojunction solar cells. And then the samples were treated as a function of the annealing temperature (300-600℃) in a vacuum. Their electrical, optical and structural properties of the fabricated heterojunction solar cells were then investigated and the power conversion efficiencies (PCE) of the fabricated p-type copper oxide/n-type Si heterojunction cells were measured using solar simulator. After being treated at temperature of 500℃, the solar cells with CuO film have PCE of 0.43%, Current density of 5.37mA/㎠, Fill Factor of 39.82%.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.489-489
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• 2011

The effect of Si quantum dots for solar cell appications was investigated. The 5 ~ 10 nm Si nanoparticle was fabricated on p-type single and poly crystalline wafer by magnetron sputtering and laser irradiation process. Scanning electron microscopy (SEM), atomic force measurement (AFM) and transmission electron microscopy (TEM) images showed that the Si QDs array were clearly embedded in insulating layer ($SiO_2$). Photoluminesence (PL) measurements reliably exhibited bandgap transitions with every size of Si QDs. The photo-current measurements were showed different result with size of QD and number of superlattice.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.84-87
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• 2014

Protection of solar cell surface is important to prevent from dust, pollen, sand, etc. Therefore, development of large area antifouling film is urgent for high performance of solar cells. The surface of silica spheres was modified to fabricate large area antifouling film. The surface of monodisperse silica spheres has been modified with 3-(trimethoxysilyl) propylmethacrylate (TMSPM) to fabricate large area photonic crystal. Although the surface modification of silica spheres with TMSPM has been failed for the base catalyst, the second trial using acid catalyst showed the following results. The FTIR absorption peak at $1721cm^{-1}$ representing C=O stretching vibration indicates that the TMSPM was attached on the surface of silica spheres. The methanol solution comprised of the surface modified silica spheres (average diameter of 380 nm) and a photoinitiator was poured in the patterned silicon wafer with the dimension of 10 cm x 10 cm and irradiated UV-light during the self-assembly process. The result showed large area crack and defect free nanostructures.