Si 이 첨가된 Al0.33Ga0.67As 에서의 Electroreflectance 에 관한 연구

김근형,김동렬,김종수,김인수,배인호,한병국 ( Geun Hyoung Kim,Dong Lyeul Kim,Jong Su Kim,In Soo Kim,In Ho Bae,Byung Kuk Han ) 한국전기전자재료학회 1997 전기전자재료학회논문지 Vol.10 No.7

Se / NH4OH 용액으로 처리시킨 n - GaAs 의 Photoreflectance 에 관한 연구

김근형,김인수,이정열,이동건,배인호,박성배 ( Geun Hyoung Kim,In Soo Kim,Jung Yeul Lee,Dong Kun Lee,In Ho Bae,Sung Bae Park ) 한국전기전자재료학회 1997 전기전자재료학회논문지 Vol.10 No.6

바베시아 원충감염 예방과 치료에 대한 비타민 E의 응용

이경갑,김근형,이영재,Lee, Kyoung-kap,Kim, Geun-hyoung,Lee, Young-jae 대한수의학회 1999 大韓獸醫學會誌 Vol.39 No.5

This study was carried out to investigate the effects of vitamin E on the prevention and treatment of Babesia gibsoni. Fifteen mongrel dogs, uninfected with Babesia spp, were assigned to three groups according to vitamin E(${\alpha}-tocopherol$) concentrations in the RBC. The concentrations in each of the three groups were, respectively : ${\alpha}-tocopherol$ in RBC less than $30{\mu}g/{\mu}l$(Group I), $30{\mu}g/{\mu}l{\sim}60{\mu}g/{\mu}l$(Group II), more than $60{\mu}g/{\mu}l$(Group III). Artificial infection was accomplished by injecting $2{\times}10^7{\sim}2{\times}10^8$ erythrocyte of Babesia gibsoni-infected dog into the cephalic vein. We investigated the clinical signs, vitamin E concentrations in RBC and serum, Vitamin A concentrations in serum, hematological values, white blood cell(WBC) viability and RBC membrane osmotic fragility after infection of Babesia gibsoni for a period of 20 days at 5 day intervals. The results obtained are summarized as follows : 1. After infection by Babesia gibsoni, clinical examination revealed depression, anorexia, pale mucous membranes, dark brown urine and diarrhea in proportion as time went on. After 10 days of infection, one dog each of Groups I, II and III revealed depression and anorexia. Two dogs in Group I and one dog each of Groups II and III showed dark brown urine after 15 days. Diarrhea was observed in one dog in each of the 3 groups after 20 days of infection. 2. After 5 days of infection, two dogs in each of Groups I, II and III showed Babesia gibsoni in RBC of blood smear stained with Giemsa. At the 15th day after infection with Babesia gibsoni, they were observed in all experimental animals. After both 5 days and 10 days of infection, the rate of Babesia gibsoni parasitized RBC(permillage, ‰) was 1‰, and increased as time went on. 3. After 5 days of infection by Babesia gibsoni, Group I, which had the lowest vitamin E concentration, showed significantly decreased RBC and PCV levels(p < 0.01). Group II and group III also showed significantly decreased RBC and PCV levels after 15 days of infection(p < 0.05). Particularly after 10 days of infection, Group I showed lower values in RBC and PCV levels compared to Groups II and III. WBC, RBC, fibrinogen and total protein levels between the groups did not differ during experimental periods. 4. According to the WBC differential counts, the ratios of neutrophil to lymphocyte showed a tendency to be slightly higher in Group III (more than $60{\mu}g/{\mu}l$) than in Groups I and II. 5. WBC viability did not differ between the groups. 6. RBC membrane osmotic fragility did not differ between the groups.

불순물이 첨가되지 않은 n - GaAs 에서의 Electroreflectance에 관한 연구

김인수(In-Soo Kim),김근형(Geun-Hyoung Kim),손정식(Jeong-Sik Son),이철욱(Chul-Wook Lee),배인호(In-Ho Bae),김상기(Sang-Gi Kim) 한국진공학회(ASCT) 1997 Applied Science and Convergence Technology Vol.6 No.2

Au/n-GaAs(100) Schottky 장벽 diode를 제작하여 변조전압(V_(ac)) 및 dc 바이어스 전압(V_(bias)) 변화에 따른 electroreflectance(ER)를 측정하였다. 관측된 Franz-Keldysh oscillation(FKO) 피크로부터 이 시료의 내부 전기장(E_i)은 5.76×10⁴V/㎝였다. V_(ac)를 변화시킴에 따라 ER 신호의 모양은 변화가 없고, 진폭만 선형적으로 증가하였다. 순방향 및 역방향의 V_(bias) 변화에 따라 ER 신호의 진폭은 감소하였으며, V_(bias)가 -5.0~0.6V로 증가함에 따라 E_i는 19.3×10⁴~4.39×10⁴V/㎝로 감소하였다. 그리고 V_(bias) 변화에 대한 E_i²의 그래프로부터 built-in 전압 (V_(bi)) 은 0.70V였으며, 이 값은 V_(bias) 변화에 따른 FKO 피크의 진폭 관계 그래프에서 얻은 결과와 잘 일치하였다. 또한 이 시료의 캐리어 농도(N)와 전위장벽(φ)은 300K 에서 각각 2.4×10^(16)㎝^(-3)와 0.78eV의 값을 얻었다. Au/n-GaAs(100) Schottky barrier diode has been investigated by using electroreflectance(ER). From the observed Franz-Keldysh oscillations(FKO), the internal electric field(E_i) of this sample is 5. 76×10⁴V/㎝ at 300 K. As the modulation voltage(V_(ac)) is changed, the line shape of ER signal does not change but its amplitude varies linearly. For increasing forward and reverse dc bias voltage(V_(bias)), the amplitude of ER signal decreases. The internal electric field decreased from 19.3×10⁴V/㎝ to 4.39×10⁴V/㎝ as V_(bias) increases from -5.0 V to 0.6 V. For Au/n-GaAs the valve of built-in voltage(V_(bi)) determined from the plot of V_(bias) versus E_i² is 0.70 V. This value agrees with that observed in the plot of V_(bias) versus amplitude of FKO peak. In addition, the carrier concentration(N) and potential barrier(Φ) of the sample at 300 K are found to be about 2.4×10^(16) ㎝^(-3) and 0.78 eV, respectively.

Al0.24Ga0.76As / GaAs 에피층에서의 표면 광전압에 관한 연구

유재인(Jae-In Yu),김도균(Do-Kjun Kim),김근형(Geun-Hyoung Kim),배인호(In-Ho Bae),김인수(In-Soo Kim),한병국(Byung-Kuk Han) 한국진공학회(ASCT) 2000 Applied Science and Convergence Technology Vol.9 No.2

Molecular beam epitaxy(MBE)로 성장시킨 Al_(0.24)Ga_(0.76)As/GaAs 에피층 구조의 표면 광전압을 측정하였다. 측정된 신호로부터 구한 Al_(0.24)Ga_(0.76)As 에피층, GaAs 기판 그리고 GaAs 완충층의 밴드갭 에너지는 각각 1.72, 1.40그리고 1.42 eV이다. 이는 photoreflectance(PR) 측정 결과와 잘 일치하였다. 그리고 Al_(0.24)Ga_(0.76)As에피층이 GaAs 기판의 표면 광전압 세기 보다 약 3배 정도 작게 나타났는데, 이는 캐리어의 이동도 차이로 나타나는 현상으로 해석된다. 또한 표면 광전압의 온도 의존성으로부터 Varshni 식의 계수들을 구하였다. We measured surface photovoltage (SPV) of Al_(0.24)Ga_(0.76)As/GaAs epilayer grown by molecular beam epitaxy (MBE). The band gap energies of Al_(0.24)Ga_(0.76)As epilayer, GaAs substrate and buffer layer obtained from SPY signals are 1.70, 1.40 and 1.42 eV, respectively. There results are in good agreements with photoreflectance (PR) measurement. The measured SPY intensity of GaAs substrate is three times larger than Al_(0.24)Ga_(0.76)Asepilayer by carrier mobility difference. The parameters of Varshni equation were determined from the SPY spectra as a function of temperature.

아르곤 플라즈마로 처리한 n - GaAs의 표면특성에 관한 Photoreflectance 연구

이동율(Dong-Yul Lee),김인수(In-Soo Kim),김동렬(Dong-Lyeul Kim),김근형(Geun-Hyoung Kim),배인호(In-Ho Bae),김규호(Kyoo-Ho Kim),한병국(Byung-Kuk Han) 한국진공학회(ASCT) 1997 Applied Science and Convergence Technology Vol.6 No.4

Power를 40 W로 고정하고 시간을 5~120초간 변화시켜 아르콘 플라즈마로 처리시킨 n-GaAs(100)의 특성을 photoreflectance(PR) 측정으로 조사하였다. 아르곤 플라즈마 처리시간을 증가시킴에 따라 E。 피크의 세기는 처리시간이 5초일 때 최소로 관측되었으며, 이때 표면전기장(E_S), 순수 캐리어농도(N_D-N_A) 및 표면상태 밀도 (Q_(SS))는 각각 1.05×10^5 V/㎝, 1.31×10^(17) ㎝-³ 및 1.64×10^(-7) C/㎡로 이 값들은 bulk 시료에 비해 약 57.1, 81.4 및 56.9% 감소하였다. 반면에 5초일 때 compensation center 농도(N_A)는 5.57×10^(17) ㎝-³로 최대였다. 그리고 아르곤 플라즈마 처리시 유발된 결함들의 침투깊이는 표면에서 약 450 Å 정도였다. We have investigated the surface characteristics of n-GaAs (100) treated with Ar plasma (40 W, 5~120 sec) by photoreflectance (PR) measurement. With increasing Ar plasma treatment time, the intensity of E。 peak observed to the minimum at 5 sec. The surface electric field (E_S), net carrier concentration (N_D-N_A), and surface state density (Q_(SS)) are 1.05×10^5 V/㎝, 1.31×10^(17) ㎝-³ and 1.64×10^(-7) C/㎡, respectively. These values were about 57.1, 81.4 and 56.9% smaller than those of bulk n-GaAs. On the other hand, the concentration of compensation centers (N_A) was maximum with value of 5.57×10^(17) ㎝-³ at 5 sec. And penetration depth of defects generated after treated with Ar plasma was about 450 Å from surface.

급속 열처리시킨 n-GaAs에서 Photoreflectance 연구

김인수,배인호,최재두,김근형 嶺南大學校 基礎科學硏究所 1997 基礎科學硏究 Vol.17 No.-

The characteristics of rapid thermal annealed n-GaAs(100) is analyzed by the photoreflectance(PR) measurement. The Si highly doped n-GaAs was observed the FKO signals. The bandgap(E?) and surface electric field(E?) of as-grown sample were 1.423 eV and 2.65×10? V/cm, respectively. In the rapid thermal annealed samples, E? was increased and then decreased by increasing anealing temperature, and it was increased again at 800 ℃. These results could be explained by decreasing of the non-radiative recombination on samples. For the time dependence of the rapid thermal annealing, the amplitude of the PR signal was maximum at 20 sec, and E? was increased by 10.7 times than that of as-grown sample.