• 한국재료학회지
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• 제18권8호
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• pp.450-453
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• 2008

Mg-doped and In-Mg co-doped p-type GaN epilayers were grown in a low-pressure metal organic chemical vapor deposition technique. The effect of In doping on the p-GaN layer was studied through photoluminescence (PL), persistent photoconductivity (PPC), and transmission electron microscopy (TEM) at room temperature. For the In-doped p-GaN layer, the PL intensity increases significantly and the peak position shifts to 3.2 eV from 2.95 eV of conventional p-GaN. Additionally, In doping greatly reduces the PPC, which was very strong in conventional p-GaN. A reduction in the dislocation density is also evidenced upon In doping in p-GaN according to TEM images. The improved optical properties of the In-doped p-GaN layer are attributed to the high crystalline quality and to the active participation of incorporated Mg atoms.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.113-114
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• 2008

Conventional furnace annealing (CFA) for activating Mg-doped p-type GaN films had been performed in pure $N_2$ ambient. All sample activated the same gas ambient. The annealing process change temperature: the first process is performed at $550^{\circ}C$ for 10 min. but, the first process is the same bulk. From second to five process increase activation temperature to change $50^{\circ}C$ and annealing time keeping for 10 min. It is found that the samples characteristic measure hall measurement. Similar results were also evidenced by photoluminescence (PL) measurement.

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 기술교육위원회 창립총회 및 학술대회 의료기기전시회
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• pp.52-59
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• 2001

The photoluminescence and the photo-current from p-type GaN films were investigated on both room- and low-temperatures for various Mg doping concentrations. At a low Mg doping level, there exists a photoluminescence center of the donor and the acceptor pair transition of the 3.28-eV band. This center is correlated with the defects for a shallow donor of the VGa and for an acceptor of MgGa. The acceptor level shows the binding energy of 0.2-0.25 eV, which was observed by the photon energy of the photo-current signal of 3.02-3.31 eV. At a high Mg doping level, there is a photoluminescence center of a deep donor and an acceptor pair transition of the 2.76-eV blue band. This center is attributed to the defect structures of MgGa-VN for the deep donor and MgGa for the acceptor. For low. doped samples, thermal annealing provides an additional photo-current signal for an unoccupied deep acceptor levels of 0.87-1.35 eV above valence band, indicating the p-type activation.

• Transactions on Electrical and Electronic Materials
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• 제11권1호
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• pp.37-41
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• 2010

The authors investigated the photoluminescence (PL) and the electron paramagnetic resonance (EPR) from an magnesium (Mg)-doped GaN thin film with a delta-doped layer. The regularly doped sample shows a PL peak at 2.776 eV for the as-grown sample, and the peak shifts to 2.904 eV and increases in intensity for the annealed sample. The delta-doped sample also shows the same PL peak as does the regularly doped sample. However, only the annealed delta-doped layer shows a sharp EPR with a small isotropic Lande g-factor, $g_{II}$, of 2.029. This resonance is attributed to the delta-doped layer, which forms a hole-bound Mg-N atomic structure instead of the $Mg_{Ga}-V_N$ defect complex, indicating that the delta-doped sample was not optically activated to form PL centers but was instead electrically activated to form a hole-bound state.

• Journal of Ceramic Processing Research
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• 제13권spc1호
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• pp.128-131
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• 2012

The selective area growth light emitting diode on GaN substrate was grown using mixed-source HVPE method with multi-sliding boat system. The GaN substrate was grown using mixed-source HVPE system. Te-doped AlGaN/AlGaN/Mg-doped AlGaN/Mg-doped GaN multi-layers were grown on the GaN substrate. The appearance of epi-layers and the thickness of the DH was evaluated by SEM measurement. The DH metallization was performed by e-beam evaporator. n-type metal and p-type metal were evaporated Ti/Al and Ni/Au, respectively. At the I-V measurement, the turn-on voltage is 3 V and the differential resistance is 13 Ω. It was found that the SAG-LED grown on GaN substrate using mixed-source HVPE method with multi-sliding boat system could be applied for developing high quality LEDs.

• 한국결정성장학회지
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• 제29권3호
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• pp.83-90
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• 2019

본 논문에서는 전력 반도체 소자용 Mg-doped AlN 에피층을 혼합 소스 수소화물 기상 에피택시 방법에 의해 성장하였다. p형 재료로는 Mg을 사용하였다. 소자응용을 위한 기초 기판으로서 역할을 하기 위하여 GaN 에피층이 성장된 기판과 GaN 에피층이 성장되어 패턴이 형성된 사파이어 기판 위에 Mg-doped AlN 에피층을 선택 성장하였다. Mg-doped AlN 에피층의 표면과 결정 구조는 FE-SEM 및 HR-XRD에 의해 조사하였다. XPS 스펙트럼과 라만 스펙트럼 결과로부터 혼합소스 HVPE 방법에 의해 성장된 Mg-doped AlN 에피층은 전력소자 등에 응용이 가능할 것으로 판단된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.23-23
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• 2003

GaN-related semiconductors are of great technological importance for the fabrication of optoelectronic devices, such as blue and ultra violet light emitting diodes (LEDs), laser diodes, and photo-detectors. One of the most important applications of GaN-based LEDs is solid-state lighting, which could replace incandescent bulbs and ultimately fluorescent lamps. For solid-state lighting applications, the achievement of high extraction efficiency in LED structures is essential. For flip-chip LEDs (FCLEDS), the formation of low resistance and high reflective p-GaN contact is crucial. So far, a wide variety of different methods have been employed to improve the ohmic properties of p-type contacts to GaN. For example, surface treatments using different chemical solutions have been successfully used to produce high-quality ohmic contacts, Metallization schemes, such as Ta/Ti contacts to p-GaN, were also investigated. For these contacts, the removal of hydrogen atoms from the Mg atoms doped n the GaN was argued to be responsible for low contact resistances.

• Transactions on Electrical and Electronic Materials
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• 제2권4호
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• pp.24-29
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• 2001

GaN films were grown for various Mg doping concentrations in metal-organic chemical vapor deposition. Below the Mg concentration of 10$^{19}$ ㎤, the thermally annealed sample shows the compensated phase to n-type GaN in Hall measurement. In the MB concentration of 4$\times$10$^{19}$ ㎤ corresponding to the hole carrier concentration of 2.6$\times$1$^{19}$ ㎤ there exists a photoluminescence center of the donor and the acceptor pair transition of the 3.28-eV band. This center is correlated with the defects for a shallow donor of the $V_{Ga}$ and for an acceptor of $Mg_{Ga}$ . The acceptor level shows the binding energy of 0.2-0.25 eV, which was observed by the photon energy of the photocurrent signal of 3.02-3.31 eV. Above the Mg concentration of 4$\times$10$^{19}$ ㎤, both the Mg doping level and Mg concentration were saturated and there Is a photoluminescence center of a deep donor and an acceptor pair transition of the 2.76-eV blue band.

• 한국결정성장학회지
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• 제9권6호
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• pp.574-579
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• 1999

암모니아가스를 역류시키는 수평식 유기금속 화학기상증착장치를 제작하였으며, 유체흐름에 관한 레이놀즈 수 및 열대류에 관한 레일리 수가 각각 4.5와 215.8이 되도록 하여 GaN 박막을 성장하였다. 이러한 특성변수에서 박막을 성장할 경우 비교적 양호한 박막의 결정특성, 전기적 특성 및 광학적 특성을 갖게 함을 확인하였다. 결정 내의 전위밀도는 $2.6{\times}10^8/\textrm {cm}^2$ 정도이었고, Si으로 도핑된 n-GaN 박막의 전자에 의한 운반자 농도와 이동도는 각각 $10^{17}$~$10^{18}/{\textrm}{cm}^3$ 과 200~400$\textrm{cm}^2$/V.sec의 범위를 갖으며 Mg을 도핑하여 후속열처리로 활성화시킨 p-GaN 박막은 정공에 의한 운반자 농도가 $8\times 10^{17}/{\textrm}{cm}^3$ 정도임을 확인하였다.