• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.44.1-44.1
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• 2011

본 연구에서는 태양전지 설계를 위해 기존의 반도체소자 simulation에 사용되고 있는 Silvaco TCAD tool을 사용하여 p+ boron emitter의 특성분석 실험을 하였다. 변수로는 emitter의 농도와 접촉저항 이 두 가지 놓고 표면 재결합과 의 영향을 염두에 두고 실험을 하였다. 농도는 $1{\times}10^{17}\;cm^{-3}$에서 $2{\times}10^{22}\;cm^{-3}$까지 두었고, 각각의 농도에 해당되는 contact 저항을 설정하여 전기적 특성을 보았다. 실험 결과 두 가지 변수를 모두 입력하였을 때 처음에 Isc가 조금씩 올라가다가 $1{\times}10^8\;cm^{-3}$에서 가장 높았고 그 이후에는 표면 재결합이 커지면서 Isc가 계속 떨어졌다. 하지만 contact 저항으로 인해 가장 높은 효율은 $1{\times}10^9\;cm^{-3}$ 부근에서 보였다. 농도에 따라 표면 재결합과 contact 저항이 서로 반대로 변하기 때문에 emitter를 표면 재결합이 늘어남에도 불구하고 contact 저항으로 인해 비교적 고농도로 doping 해야만 했다. 하지만 우리가 준 contact 저항은 농도에 따라 생긴 저항으로 실제 전극의 contact 저항은 훨씬 더 클 것으로 예상되고 이로 인해 더 고농도의 doping이 필요하게 된다. 그렇게 된다면 표면의 재결합으로 인한 손실은 더 크게 되어 전체적으로 효율은 떨어진다. 우리는 이 손실을 보완하고 줄이기 위해 selective emitter 개념을 넣어 이에 대한 영향은 보았다. selective를 하지 않은 $1{\times}10^{19}\;cm^{-3}$의 doping 농도의 가장 높은 효율을 보인 기존의 emitter와 전극 부분을 제외한 표면은 $1{\times}10^{18}\;cm^{-3}$으로 하고 전극 부분의 emitter는 $2{\times}10^{20}\;cm^{-3}$으로 한 selective emitter를 비교해보았다. 이는 selective emitter가 기존 emitter에 비해 Isc와 Fill Factor로 인해 효율이 약 0.7% 정도 높았다.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.509-514
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• 2020

The two key variables of an Si solar cell, i.e., emitter (n-type window layer) and base (p-type substrate) doping levels or concentrations, are studied using Medici, a 2-dimensional semiconductor device simulation tool. The substrate is p-type and 150 ㎛ thick, the pn junction is 2 ㎛ from the front surface, and the cell is lit on the front surface. The doping concentration ranges from 1 × 10¹⁰ cm^-3 to 1 × 10²⁰ cm^-3 for both emitter and base, resulting in a matrix of 11 by 11 or a total of 121 data points. With respect to increasing donor concentration (Nd) in the emitter, the open-circuit voltage (Voc) is little affected throughout, and the short-circuit current (Isc) is affected only at a very high levels of Nd, exceeding 1 × 10¹⁹ cm^-3, dropping abruptly by about 12%, i.e., from Isc = 6.05 × 10^-9 A·㎛^-1, at Nd = 1 × 10¹⁹ cm^-3 to Isc = 5.35 × 10^-9 A·㎛^-1 at Nd = 1 × 10²⁰ cm^-3, likely due to minority-carrier, or hole, recombination at the very high doping level. With respect to increasing acceptor concentration (Na) in the base, Isc is little affected throughout, but Voc increases steadily, i.e, from Voc = 0.29 V at Na = 1 × 10¹² cm^-3 to 0.69 V at Na = 1 × 10¹⁸ cm^-3. On average, with an order increase in Na, Voc increases by about 0.07 V, likely due to narrowing of the depletion layer and lowering of the carrier recombination at the pn junction. At the maximum output power (Pmax), a peak value of 3.25 × 10^-2 W·cm^-2 or 32.5 mW·cm^-2 is observed at the doping combination of Nd = 1 × 10¹⁹ cm^-3, a level at which Si is degenerate (being metal-like), and Na = 1 × 10¹⁷ cm^-3, and minimum values of near zero are observed at very low levels of Nd ≤ 1 × 10¹³ cm^-3. This wide variation in Pmax, even within a given kind of solar cell, indicates that selecting an optimal combination of donor and acceptor doping concentrations is likely most important in solar cell engineering.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.12
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• pp.1019-1025
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• 2021

In nearly all space environments, the solar cell degradation is dominated by protons[1]. Even through a GEO orbit lines in the electron radiation belts, the protons emitted from any solar event will still dominate the degradation[1]. Since COMS launch on June 26 2010, the proton events with the fluence of more than approximately 30 times the average level of perennial observations were observed between January 23 - 29 2012 and March 07 - 14 2012[16]. This paper studies the solar cell degradation by solar proton events in January and March 2012 for the open circuit voltage(Voc) of a witness cell and the short circuit current(Isc) of a section connected to a shunt switch. To evaluate the performance of solar cell, the flight data of voltage and current are corrected to the temperature, the Earth-Sun distance and the Sun angle and then compare with the solar cell characteristics at BOL. The Voc voltage dropped about 23.6mV compare after the March 2012 proton events to before the January 2012 proton events. The Voc voltage dropped less than 1% at BOL, which is 2575mV. The Isc current decreased negligible, as expected, in the March 2012 proton events.

• Proceedings of the Microbiological Society of Korea Conference
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• 2006.05a
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• pp.69-71
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• 2006

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3853-3858
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• 2010

This paper shows electrical analysis of the silicon solar cell according to the various ARC thickness using Medici program. we built a mesh structure of the solar cell that use ARC consisting of ITO(Indium-Tin-Oxide) transparent electrode, for the Medici modeling. About various oxide layer thickness of the ARC for 30 nm, 60 nm, 90 nm, changes of the I-V curve, Isc, Voc, transmittance and external collection efficiency performed according to wavelength of Incident ray. Simulation results show maximum power 22 mW/$cm^2$, fill factor 0.83 in condition of 60 nm ITO thickness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2212-2217
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• 2010

Previous studies have been focused on the voltage of Bypass diode and Isc(Short Circuit Current) of the influenced solar cell. The Bypass diode starts working when it gets the reverse applied voltage. Previous studies have only concentrated on Isc of the influenced solar cell and Imp of PV module to explain the bypassing performance. PV module is usually working together with inverter having MPPT(Maximum Power Point Tracking) function for best performance. bypassing point is regulated by MPPT function of inverter. In this paper, simulation results of Bypass diode in PV module have been analyzed to represent the relationship of the bypassing point with the composition of PV module. From the results, the more cells are connected with each string, the earlier bypassing performance happens under the fixed number of strings. As diode groups increase or irradiation decreases, the bypassing performance starts fast.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2963-2967
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• 2010

In this paper, we have predicted and analyzed the MSX 60 photovoltaic module's output according to the temperature and solar radiation conditions by MATLAB program. 2 and 3-dimensional I-V curves of the PV module considered temperature, series resistance and solar radiation variation. are shown. Also, calculated PV's electrical parameters are Isc = 3.8 A, Voc = 21 V, Pmax = 60 W. Compared with the actual photovoltaic module's data, these simulated results agreed well with within the manufacturer's maximum error range 3%.

• Journal of KSNVE
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• v.8 no.3
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• pp.542-552
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• 1998

The noise sources, structure-borne and/or air-borne, in machinery can be defined by their locations and strengths. However the locations of that noise sources are well known in many cases. In those cases, the problem can be defined as an inverse problem to known the strengths of the noise sources in the frequency domain, the modeling scheme is classified by thecoherent or incoherent source. This paper expands the basic concept to the case of the complex noise sources, in which the set of coherent and incoherent noise sources are matched with the noise of a real vehicle. The error factors in the experiment and the optimal number of the monopole sources to match the real suond filed are also investigated. The results of the noise source modeling of heavy machinery show that the incoherent and coherent/incoherent source models are applicable to the high frequency and the low frequency region, respectively. The noise source model also enables the noise source analysis to rank the contribution of real source group such as engine, T/M, exhuast, etc.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.93-99
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• 2011

To guarantee more exact maximum power of solar cell module, it is absolutely required to have performance characteristics of various solar cells. Today, there are many types of solar simulator for large area measurement. But it is very opaque how to select the best one for various solar cell module like crystalline silicon solar cell, high efficiency solar cell, amorphous silicon thin film solar cell, CdTe and CIGS solar cell module. So, in this paper 4 types of photovoltaic module were selected to compare the electrical characteristics by changing light pulse duration time and voltage scan direction. Light pulse duration time was varied from 10msec to 800msec. And two types of voltage scan directions, Voc->Isc and Isc->Voc were selected. From this results, optimum measuring condition was suggested and electrical variation was analysed for each types of solar cell module. The detail description is specified as the following paper.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.611-616
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• 2021

This paper investigates the improved outage probability of correlated superposition coding(CSC)/non-successive interference cancellation(SIC) non-orthogonal multiple access(NOMA) scheme. For this, first, we calculate the outage probability of the conventional independent superposition coding(ISC)/SIC NOMA scheme. Then, simulations demonstrate that the outage probability of CSC/non-SIC NOMA improves greatly, with respect to that of conventional ISC/SIC NOMA. As a result, CSC/non-SIC NOMA schemes could be a promising technique in 5G networks, especially with such improved outage probability.