• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.372-375
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• 2017

ZnO thin films were deposited by RF magnetron sputtering and then diffused by using an As source in the ampouletube. Also, the ZnO p-n homojunction was made by using As-doped ZnO thin films, and its properties were analyzed. After the As doping, the surface roughness increased, the crystal quality deteriorated, and the full width at half maximum was increased. The As-doped ZnO thin films showed typical p-type properties, and their resistivity was as low as $2.19{\times}10^{-3}{\Omega}cm$, probably because of the in-diffusion from an external As source and out-diffusion from the GaAs substrate. Also, the ZnO p-n junction displayed the typical rectification properties of a p-n junction. Therefore, the As diffusion method is effective for obtaining ZnO films with p-type properties.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.29-33
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• 2005

In this paper, reflectance and the dielectric characteristics for $P_2O_5-ZnO-BaO$ system and $SiO_2-ZnO-B_2O_3$ system have been investigated as a function of contents of $TiO_2$. The reflectance was decreased with increasing the contents of $TiO_2$ and the reflectance of $P_2O_5-ZnO-BaO$ system was lowered than that of $SiO_2-ZnO-B_2O_3$ system. The dielectric constant of $P_2O_5-ZnO-BaO$ system was higher than $SiO_2-ZnO-B_2O_3$ system, and the dielectric constant in the both system was increased with increasing of $TiO_2$ contents. This can be explained as the space charge effects. These results are could be applied to the under plate dielectrics of PDP required high reflective ratio and breakdown strength.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.17-21
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• 2001

We proposed that concentrations of cartier electron as well as ionized donor defects in nonstoichiometric ZnO are proportional to $P^{-1/2}_{O_2}$, whenever they ionizes singly or doubly, by employing the Fermi-Dirac (FD) statistics for ionization of the native thermal defects $Zn_i$ and $V_o$. The effect of acceptor defect, zinc vacancy $V_{Zn}$made by the Frenkel and Schottky disorder reactions, on carrier concentrations was discussed. By application of the FD statistics law to their ionization while the formation of defects is assumed governed by the mass-action law, the calculation results indicate; 1. ZnO shows n-type conductivity with $N_D>$N_A$ and majority concentration of $n{\propto}\;P^{-1/2}_{O_2}$ in a range of $P_{O_2}$, lower than a critical value. 2. As the concentration of acceptor $V_{Zn}$ increases proportional to $P^{1/2}_{O_{2}}$, ZnO made at extremely high $P_{O_{2}}$, can have p-type conductivity with majority concentration of p ${\propto}\;P^{-1/2}_{O_{2}}$. One may not, however, obtain p-type ZnO if the pressure for $N_{D}<$N_{A}$ is too high.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.408-409
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• 2007

Al-doped p-type ZnO films were fabricated on n-Si (100) and homo-buffer layers in pure oxygen at $450^{\circ}C$ by RF magnetron sputtering. Target was ZnO ceramic mixed with 2wt% $Al_2O_3$. XRD spectra show that the Al-doped ZnO thin films have ZnO crystal structure and homo-buffer layers are beneficial to Al-doped ZnO films to grow along c-axis. Hall Effect experiments with Van der Pauw configuration show that p-type carrier concentrations are ranged from $1.66{\times}10^{16}\;to\;4.04{\times}10^{18}cm^{-3}$, mobilities from 0.194 to $2.3cm^2V^{-1}s^{-1}$ and resistivities from 7.97 to $18.4{\Omega}cm$. P-type sample has density of $5.40cm^{-3}$ which is smaller than theoretically calculated value of $5.67cm^{-3}$. XPS spectra show that O1s has O-O and Zn-O structures and A12p has only Al-O structure. P-ZnO:Al/n-ZnO:Al junctions were fabricated by magnetron sputtering. V-I curves show that the p-n junctions have rectifying characteristics.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.1-3
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• 2002

A p-n junction was obtained by the deposition of an n-type ZnO thin film on a p-type Zn-doped InP substrate. The Zn-doped InP substrate has been made by the diffusion of Zn with sealed ampoule technique. The ZnO deposition process was performed by pulsed laser deposition (PLD). The p-n junction was formed and showed typical I-V characteristics. We will also discuss about the realization of an ultraviolet light-emitting diode (LED). The structure of n-ZnO/p-Zn-doped InP could be a good candidate for the realization of an ultraviolet light-emitting diode or an ultraviolet laser diode.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.87.1-87.1
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• 2012

넓은 밴드갭 (3.37eV)과 높은 엑시톤 결합에너지 (60meV)를 가지는 ZnO 물질은 ultra violet light 센서 및 light emitting diode (LED)의 재료로써 많은 연구가 진행되고 있다. 특히 나노와이어 구조를 이용하여 소자를 만들 경우 양자효과와 1차원적 캐리어 수송경로 효과로 인하여 그 특성을 보다 향상 시킬 수 있다. 나노와이어를 이용한 이종접합 p-n 다이오드를 제작하기 위하여 ZnO와 격자상수가 비슷한 GaN, NiO, CoO와 같은 물질들이 나노구조 접합에 많이 쓰이고 있지만, 격자상수 차이로 인해서 접합부분 캐리어 수송효율이 떨어지는 단점을 가지고 있다. n-type과 p-type ZnO를 만들어 동종 접합을 만들 경우 이러한 문제점을 극복할 수 있지만, 도핑되지 않은 ZnO가 n-type을 특성을 나타내기 때문에 안정적인 p-type ZnO 합성에 대한 연구가 필수적이다. 본 연구에서는 안정적인 p-type ZnO 합성을 위해서 수열합성법을 이용하여 phosphorus (P) 도핑을 하였고, 나노와이어 diode 구조를 만들었다. P 도핑으로 인한 격자상수 변화는 x-ray diffraction (XRD)를 사용하여 확인하였고, x-ray photoelectron spectroscopy (XPS)를 통해 도핑 원소를 분석하였으며, 이때의 recification ratio, turn-on voltage 등의 전기적 특성을 평가하였다.

• Korean Journal of Materials Research
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• v.23 no.5
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• pp.255-259
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• 2013

An effect of thermal annealing on activating phosphorus (P) atoms in ZnO nanorods (NR) grown using a hydrothermal process was investigated. $NH_4H_2PO_4$ used as a dopant source reacted with $Zn^{2+}$ ions and $Zn_3(PO_4)_2$ sediment was produced in the solution. The fact that most of the input P elements are concentrated in the $Zn_3(PO_4)_2$ sediment was confirmed using an energy dispersive spectrometer (EDS). After the hydrothermal process, ZnO NRs were synthesized and their PL peaks were exhibited at 405 and 500 nm because P atoms diffused to the ZnO crystal from the $Zn_3(PO_4)_2$ particles. The solubility of the $Zn_3(PO_4)_2$ initially formed sediment varied with the concentration of $NH_4OH$. Before annealing, both the structural and the optical properties of the P-doped ZnO NR were changed by the variation of P doping concentration, which affected the ZnO lattice parameters. At low doping concentration of phosphorus in ZnO crystal, it was determined that a phosphorus atom substituted for a Zn site and interacted with two $V_{Zn}$, resulting in a $P_{Zn}-2V_{Zn}$ complex, which is responsible for p-type conduction. After annealing, a shift of the PL peak was found to have occurred due to the unstable P doping state at high concentration of P, whereas at low concentration there was little shift of PL peak due to the stable P doping state.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.575-579
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• 2008

Al-doped p-type ZnO films were fabricated on n-Si (100) and homo-buffer layers in pure oxygen at $450^{\circ}C$ of by RF magnetron sputtering. Target was ZnO ceramic mixed with 2 wt% $Al_2O_3$. XRD spectra show that the Al-doped ZnO thin films have ZnO crystal structure and homo-buffer layers are beneficial to Al-doped ZnO films to grow along c-axis. Hall Effect experiments with Van der Pauw configuration show that p-type carrier concentrations are ranged from $1.66{\times}10^{16}$ to $4.04{\times}10^{18}\;cm^{-3}$, mobilities from 0.194 to $2.3\;cm^2V^{-1}s^{-1}$ and resistivities from 7.97 to $18.4\;{\Omega}cm$. p-type sample has density of $5.40\;cm^{-3}$ which is smaller than theoretically calculated value of $5.67\;cm^{-3}$. XPS spectra show that Ols has O-O and Zn-O structures and Al2p has only Al-O structure. P-ZnO:Al/n-ZnO:Al junctions were fabricated by magnetron sputtering. V-I curves show that the p-n junctions have rectifying characteristics.

• Korean Journal of Materials Research
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• v.21 no.1
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• pp.34-38
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• 2011

In this study, the effects of an annealed buffer layer with different thickness on heterojunction diodes based on the ZnO/ZnO/p-Si(111) systems were reported. The effects of an annealed buffer layer with different thickness on the structural, optical, and electrical properties of zinc oxide (ZnO) films on p-Si(111) were also studied. Before zinc oxide (ZnO) deposition, different thicknesses of ZnO buffer layer, 10 nm, 30 nm, 50 nm and 70 nm, were grown on p-Si(111) substrates using a radio-frequency sputtering system; samples were subsequently annealed at $700^{\circ}C$ for 10 minutes in $N_2$ in a horizontal thermal furnace. Zinc oxide (ZnO) films with a width of 280nm were also deposited using a radio-frequency sputtering system on the annealed ZnO/p-Si (111) substrates at room temperature; samples were subsequently annealed at $700^{\circ}C$ for 30 minutes in $N_2$. In this experiment, the structural and optical properties of ZnO thin films were studied by XRD (X-ray diffraction), and room temperature PL (photoluminescence) measurements, respectively. Current-voltage (I-V) characteristics were measured with a semiconductor parameter analyzer. The thermal tensile stress was found to decrease with increasing buffer layer thickness. Among the ZnO/ZnO/p-Si(111) diodes fabricated in this study, the sample that was formed with the condition of a 50 nm thick ZnO buffer layer showed a strong c-axis preferred orientation and I-V characteristics suitable for a heterojunction diode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.