• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1056-1060
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• 2005

We investigated the fabrication and characteristics of the nitride-based spin-polarized LEDs with room-temperature ferromagnetic (Ga,Mn)N layer as a spin injection source. The (Ga,Mn)N thin films having room-temperature ferromagnetic ordering were found to exhibit the negative MR and anomalous Hall resistance up to room temperature, revealing the existence of spin-polarized electrons in (Ga,Mn)N films at room temperature. The electrical characteristics in the spin LEDs did not degraded in spite of the insertion of the (Ga,Mn)N layer into the LED structure. In EL spectra of the spin LEDs, it is confirmed that the devices produce intense EL emission at 7 K as well as room temperature. These results are expected to open up new opportunities to realize room-temperature operating semiconductor spintronic devices.

• 한국결정성장학회지
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• 제14권1호
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• pp.33-36
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• 2004

고밀도 GaN 타겟의 레이저 어블레이션으로 상온에서 비정질 GaN 박막을 제조하였다. 다양한 Ar 압력 및 레이저 에너지로 증착된 박막의 표면미세구조 및 조성분석 결과, 10Pa의 압력하에 증착된 박막은 smooth한 표면을 갖는 비정질 GaN로 구성되었음을 확인하였으며, 특히 200mJ/pu1se로 증착된 박막은 저 에너지에서 증착된 박막과 비교하여 결정성의 증가 및 화학양론에 가까운 조성을 나타냈다. 상온 photoluminescence spectra로부터 비정질 GaN 박막은 약 2.8eV에서 강한 band gap발광특성이 관측되었으며, 200mJ/pu1se의 10 Pa에서 가장 높은 발광효율을 나타냈다.

• 대한화학회지
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• 제40권3호
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• pp.167-172
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• 1996

GaN 단결정 박막은 halide vapor phase epitaxy(HVPE)방법을 사용하여 사파이어 기판위에 헤케로에피탁시하게 성장시켰다. 이렇게 제조된 박막은 n형 전동성을 갖는다. 아연(Zn)을 받개 불순물로 도핑시켜 절연형 GaN 박막을 만들었는데 2.64과 2.43eV의 청색영역에서 발광 피크를 가졌다. 본 연구에의해 GaN 박막은 MIS(metal-insulator-semiconductor) 접합구조로 제작이 가능함을 시사하였고, 이종접합형 발광소자 개발에 기초자료가 될 것으로 전망된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.150-152
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• 2005

We investigated the fabrication and characteristics of spin-polarized LEDs based on GaN using (Ga,Mn)N as spin injection source. (Ga,Mn)N thin films were found to exhibit the ferromagnetic ordering above room temperature and the negative MR up to room temperature. The electrical characteristics in spin LEDs did not degraded in spite of the insertion of (Ga,Mn)N films. In EL spectra of spin LEDs, it is confirmed that spin LEDs emit the strong light at 7 K as well as room temperature. These results suggest that it is possible to emit spin-polarized light in our spin LEDs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.574-577
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• 2001

GaN thin films on sapphire were grown by rf magnetron sputtering with ZnO buffer layer. The dependence of GaN film quality on ZnO buffer layer was investigated by X-ray diffraction(XRD). The improved film quality has been obtained by using thin ZnO buffer layer. Using Auger electron spectroscopy(AES), it was observed that the annealing process improved the GaN film quality. The surface roughness according to the annealing temperatures(700, 900, 1100$^{\circ}C$) were investigated by AFM(atomic force microscopy) and it was confirmed that the crystallization was improved by increasing the annealing temperature. Photoluminescence at 8K shows a near-band-edge peak at 3.2eV with no deep level emission.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 추계학술발표강연 및 논문개요집
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• pp.87-87
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• 1999

• 한국진공학회:학술대회논문집
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• 한국진공학회 1996년도 제11회 학술발표회 논문개요집
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• pp.22-23
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• 1996

• 한국재료학회:학술대회논문집
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• 한국재료학회 2001년도 춘계학술발표강연 및 논문개요집
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• pp.106-106
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• 2001

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.267-270
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• 1999

We measured the dielectr~c constant of undoped GaN thin films grown on (0001) sapphire substrates In 0.8 - 4.5 eV energy (276 - 1550 nm wavelength) range by spectroscopic ellipsometry. For more accurate data analysis we also performed X-ray diffraction, photolurninescence and Rutherford backscattering spectroscopy on samples. Data were analyzed with a four-phase model. The dielectric constant of GaN thin films was obtained not only in the transparent region but also around the absorption edge. Absorption edge energy, $3.3992{\pm}0.002$eV was determined from the obtained dielectric function.

• 반도체디스플레이기술학회지
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• 제4권2호
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• pp.1-5
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• 2005

Electon spin resonance measurements have been performed on the Mg-doped wurtzite GaN thin films grown on sapphire substrates by low-pressure metal-organic chemical vapor deposition. The sample set included films as-grown with the regular Mg doped and Mg delta doped samples and the corresponding annealed ones. The resonance signal has been observed from the annealed Mg delta-doped sample with the Lande g value of 2.029. This indicates that the singlet resonance signal originates from the neutral Mg acceptor located at 0.24 eV above the valence band edge and 0.13 eV above the Fermi level because of the nuclear hyperfine spin 1=0 of Mg and the larger value than the free electron g=2.0023.