• 대한디지털의료영상학회논문지
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• 제8권1호
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• pp.51-55
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• 2006

moving photocarrier grating(MPG)기술을 이용하여 디지털 X-선 변환물질 a-Se:As 필름에서 As 첨가효과에 관하여 연구하였다. 이 방법은 시료를 조사하기 위하여 주파수를 변화시킨 2개 레이저 빔의 중첩으로 얻어진 움직이는 간섭패턴을 이용한다. 시료의 수송변수는 시료에서 변조 방향으로 유도되는 grating-속도에 의존하는 전류밀도로부터 얻어진다. As 첨가에 따른 a-Se 필름의 전자와 정공 이동도 그리고 재결합 수명을 구하였다. 전자의 이동도는 결함 상태 때문에 As 첨가에 따라 감소하는 반면, 특히 a-Se 필름에 0.3% As 첨가할 때 정공 이동도와 재결합 수명이 증가하였다. MPG 기술로 얻은 As가 첨가된 a-Se 필름의 수송성질을 a-Se:As로 제작한 X-선 detector의 X-선 감도와 비교하였다. 실험결과 0.3% As가 첨가된 a-Se으로 제작한 X-선detector가 가장 우수한 X-선 감도를 나타내었다.

• 대한방사선기술학회지:방사선기술과학
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• 제28권4호
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• pp.267-272
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• 2005

moving photocarrier grating 기술을 이용하여 디지털 X-선 변환물질 a-Se:As 필름에서 As 첨가효과에 관하여 연구하였다. 이 방법은 시료를 조사하기 위하여 주파수를 변화시킨 2개 레이저 빔의 중첩으로 얻어진 움직이는 간섭패턴을 이용한다. 시료의 수송변수는 시료에서 변조 방향으로 유도되는 grating-속도에 의존하는 전류밀도로부터 얻어진다. As 첨가에 따른 a-Se 필름의 전자와 정공 이동도 그리고 재결합 수명을 구하였다. 전자의 이동도는 결함 상태 때문에 As 첨가에 따라 감소하는 반면, 특히 a-Se 필름에 0.3% As 첨가할 때 정공 이동도와 재결합 수명이 증가하였다. MPG 기술로 얻은 As가 첨가된 a-Se 필름의 수송성질을 a-Se:As로 제작한 X-선 디텍터의 X-선 감도와 비교하였다. 실험결과 0.3% As가 첨가된 a-Se으로 제작한 X-선 디텍터가 가장 우수한 X-선 감도를 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.55-56
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• 2006

We investigated the diffraction grating efficiency by the DPSS laser beam wavelength to improve the diffraction efficiency on AsGeSeS & Ag/ AsGeSeS thin film. Diffraction efficiency was obtained from DPSS(532nm)(P:P)polarized laser beam on AsGeSeS, Ag/ AsGeSeS and AsGeSeS/Ag/AsGeSeS thin films. As a result, for the laser beam intensity, 0.24 mW, single AsGeSeS thin film shows the highest value of 0.161% diffraction efficiency at 300 s and for 2.4 mW, it was recorded with the fastest speed of 50 s, which the diffraction grating forming speed is faster than that of 0.24 mW beam. Ag/ AsGeSeS and AsGeSeS/ Ag/ AsGeSeS multi-layered thin film also show the faster grating forming speed at 2.4 mW and higher value of diffraction efficiency at 0.24 mW.

• 한국진공학회지
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• 제7권1호
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• pp.11-16
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• 1998

본 연구에서는 GaAs의 selenium보호막형성 효과를 관찰하기 위하여 $Na_2$Se/NH$_4$OH 용액을 제조하고 X-선 광전자 분광기(X-ray photoelectron spectroscopy)와 photoluminescence(PL)를 이용하여 표면처리된 GaAs의 처리직후 및 대기중 노출에 따른 화학적 결합특성 및 광학적 특성을 관찰하였다. 용액처리 직후, 표면에는 As-Se결합이 형성 되었으며 Se는 한가지 산화상태인 -2가로 존재함이 관찰되었다. 또한 세정처리후의 표면보 다 Se용액처리 이후에 PL의 피이크 세기가 크게 증가됨으로부터 Se 용액처리가 GaAs의 표면상태밀도를 효과적으로 감소시킬 수 있음을 확인할 수 있었다. 그러나 처리 직후 공기 중 노출없이 관찰한 GaAs표면에서 산화막이 국부적으로 관찰되었으며 이렇게 처리과정중 생성된 산화막은 대기중 노출에 따라 산화막 성장을 유도하고 표면처리 효과를 저하시키는 주요인으로 작용함을 알 수 있었다. 이는 Se용액처리된 GaAs표면의 PL강도가 대기중 노출 에 따라 감소하며 세정처리후 GaAs표면의 PL강도와 유사한 값을 나타냄으로 부터도 확인 할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제9권5호
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• pp.551-556
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• 1996

Selenium (Se) apparent absorption and retention in sheep as influenced by diets differing in protein content through soybean meal supplementation was studied. A $3{\times}3$ Latin square design was used with three Japanese Corriedale wethers (45 kg average body weight), three periods, and three dietary treatments. In each period, 7 d dietary adjustment was followed by 5 d total collection of urine and feces. The three dietary treatments were : Diet 1, without soybean meal supplementation (14% crude protein, CP); Diet 2, with 10% soybean meal supplementation (16.5% CP); and Diet 3, with 20% soybean meal supplementation (19% CP). All the diets had a Se supplementation in the form of sodium selenite at 0.2 mg Se/kg dietary DM. The dietary DM intake of the animals was 2% of their body weight. No significant differences were obtained among the three dietary treatments of the Se balance of the animals. However, as percent of Se intake, only urinary Se concentration of Diet 3 was markedly lower (p < 0.05) than the other diets. Fecal Se as percent of Se intake followed the trend of Diet 3> Diet 2 > Diet 1 resulting a Se absorbed as percent of Se intake of 58.9%, 62.3% and 68.2% for Diets 3, 2 and 1, respectively but their differences among each other were insignificant. No significant differences that were observed either on Se retained as percent of intake (Diet 1, 48.2%; Diet 2, 45.2%; Diet 3, 46.0%) or Se retained as percent of Se absorbed (Diet 1, 70.7%; Diet 2, 72.4%; Diet 3, 77.9%). Significant correlation coefficients among the various measures of Se utilization were also observed. Regression analysis showed the following equation: Y = 93.8 - 1.86X (p <0.05, $r^{2}=0.48$), where Y is the Se absorbed as percent of Se intake (%) and X is the dietary protein content (%). This study concludes that Se requirement in sheep is greater when dietary protein content is high.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.84-84
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• 2003

The ZnSe epilayers were grown on the GaAs substrate by hot wall epitaxy. After the ZnSe epilayers treated in the vacuum-, Zn-, and Se-atmosphere, respectively, the defects of the epilayer were investigated by means of the low-temperature photoluminescence measurement. The dominant peaks at 2.7988 eV and 2.7937 eV obtained from the PL spectrum of the as-grown ZnSe epilayer were found to be consistent with the upper and the lower polariton peak of the exciton, I$_2$ (D$^{\circ}$, X), bounded to the neutral donor associated with the Se-vacancy. This donor-impurity binding energy was calculated to be 25.3meV The exciton peak, lid, at 2.7812 eV was confirmed to be bound to the neutral acceptor corresponded with the Zn-vacancy. The I$_1$$\^$d/ peak was dominantly observed in the ZnSe/GaAs:Se epilayer treated in the Se-atmosphere. This Se-atmosphere treatment may convert the ZnSe/GaAs:Se epilayer into the p-type. The SA peak was found to be related to a complex donor like a (V$\sub$se/ - V$\sub$zn/) - V$\sub$zn-/

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.120-123
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• 2003

The ZnSe epilayers were grown on the GaAs substrate by hot wall epitaxy. After the ZnSe epilayers treated in the vacuum-, Zn-, and Se-atmosphere, respectively, the defects of the epilayer were investigated by means of the low-temperature photoluminescence measurement. The dominant peaks at 2.7988 eV and 2.7937 eV obtained from the PL spectrum of the as-grown ZnSe epilayer were found to be consistent with the upper and the lower polariton peak of the exciton, $I_2$ ($D^{\circ}$, X), bounded to the neutral donor associated with the Se-vacancy. This donor-impurity binding energy was calculated to be 25.3 meV. The exciton peak, $I_1^d$, at 2.7812 eV was confirmed to be bound to the neutral acceptor corresponded with the Zn-vacancy. The $I_1^d$ peak was dominantly observed in the ZnSe/GaAs:Se epilayer treated in the Se-atmosphere. This Se-atmosphere treatment may convert the ZnSe/GaAs:Se epilayer into the p-type. The SA peak was found to be related to a complex donor like a $(V_{Se}-V_{Zn})-V_{Zn}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.282-283
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• 2006

The transport phenomena of arsenic (As) doped amorphous selenium(a-Se:As) thin film for digital X-ray conversion material has been reported. The effect of As addition on the carrier mobility and recombination lifetime in a-Se:As sample has been measured using the moving photo-carrier grating (MPG) technique. An Increase in hole mobility and recombination was observed when 0.3% arsenic, was added into a-Se sample, whereas electron mobility decrease with arsenic addition due to the defect density. The fabricated a-Se:03% As device exhibited the highest X-ray sensitivity.

• 현장농수산연구지
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• 제5권1호
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• pp.36-56
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• 2003

Selenium(Se) is an essential trace element in the human body. Main function of this element is a catalytic part of antioxidant enzymes that protect cells against the attacks of free radicals that are produced during normal metabolism of the body. Se is also essential for normal function of the immune system and thyroid gland. It also appears to be a key nutrient in counteracting the development of virulence and inhibiting HIV(human immunodeficiency virus) progression to AIDS. It is also required for sperm motility and reduces the depression. Therefore, it is very meaningful that livestock producers generate Se-fortified animal products, such as Se-egg, Se-milk, Se-pork, Se-chicken and Se-beef from the point of producers as well as human heath. However, regulation on Se usage and Se-fortified food/feed is far from being clear in Korea even though Se should be carefully monitored because of its toxicity. Thus, one has to be aware of Se properties when designing Se-fortified animal products.

• Current Photovoltaic Research
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• 제3권3호
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• pp.85-90
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• 2015

Two-step processes for preparing $Cu(In,Ga)Se_2$ absorber layers consist of precursor layer formation and subsequent annealing in a Se-containing atmosphere. Among the various deposition methods for precursor layer, the nonvacuum (wet) processes have been spotlighted as alternatives to vacuum-based methods due to their potential to realize low-cost, scalable PV devices. However, due to its porous nature, the precursor layer deposited on Mo substrate by nonvacuum methods often suffers from thick $MoSe_2$ formation during selenization under a high Se vapor pressure. On the contrary, selenization under a low Se pressure to avoid $MoSe_2$ formation typically leads to low crystal quality of absorber films. Although TiN has been reported as a diffusion barrier against Se, the additional sputtering to deposit TiN layer may induce the complexity of fabrication process and nullify the advantages of nonvacuum deposition of absorber film. In this work, Mo oxide layers via thermal oxidation of Mo substrate have been explored as an alternative diffusion barrier. The morphology and phase evolution was examined as a function of oxidation temperature. The resulting Mo/Mo oxides double layers were employed as a back contact electrode for $CuInSe_2$ solar cells and were found to effectively suppress the formation of $MoSe_2$ layer.