• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.3
• /
• pp.472-476
• /
• 2007

In this study, we investigated methods for p-type ZnO deposition as well as stability enhancement of its properties. The film was prepared by co-depositing AlAs and ZnO in a RF magnetron sputtering system. Property variation was monitored with photoluminescence and Hall measurements by stressing the films at $250^{\circ}C$ for various duration upto 144 hours. Results indicated that co-deposition is a useful method for p-type ZnO preparation. In particular, pre-treatment in 30% $H_2O_2$ for 1min was observed to be effective in reducing the property variation taking place during the subsequent high temperature processes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.126-129
• /
• 2001

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 a typical I-V characteristic. 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 Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11a
• /
• pp.126-129
• /
• 2001

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 ws performed by pulsed laser deposition (PLD). The p-n junction was formed and showed a typical I-V characteristic. 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.

• Transactions on Electrical and Electronic Materials
• /
• v.10 no.1
• /
• pp.24-27
• /
• 2009

N-doped ZnO thin films were deposited on n-type Si(100) and homo-buffer layer, and undoped ZnO thin film was also deposited on homo-buffer layer by RF magnetron sputtering method. After deposition, all films were in-situ annealed at $800^{\circ}C$ for 5 minutes in ambient of $O_2$ with pressure of 10Torr. X -ray diffraction shows that the homo-buffer layer is beneficial to the crystalline of N-doped ZnO thin films and all films have preferable c-axis orientation. Atomic force microscopy shows that undoped ZnO thin film grown on homo-buffer layer has an evident improvement of smoothness compared with N-dope ZnO thin films. Hall-effect measurements show that all ZnO films annealed at $800^{\circ}C$ possess p-type conductivities. The undoped ZnO film has the highest carrier concentration of $1.145{\times}10^{17}cm{-3}$. The photoluminescence spectra show the emissions related to FE, DAP and many defects such as $V_{Zn}$, $Zn_O$, $O_i$ and $O_{Zn}$. The p-type defects ($O_i$, $V_{Zn}$, and $O_{Zn}$) are dominant. The undoped ZnO thin film has a better p-type conductivity compared with N-doped ZnO thin film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.143-143
• /
• 2010

In this study, we demonstrate that ZnO deposited onto $SiO_2$ substrates by magnetron sputtering produces p-type ZnO at higher $O_2$ pressure and n-type ZnO at lower $O_2$ pressure. We also report the effect of hydrogen peroxide ($H_2O_2$) on the stability of undoped ZnO thin films. The films were immersed in 30% $H_2O_2$ for 1 min at $30^{\circ}C$ and annealed in $O_2$at $450^{\circ}C$. The carrier concentration, mobility. and conductivity were measured by a Hall effect measurement system. The Hall measurement results for ZnO films untreated with $H_2O_2$ but annealed in $O_2$ indicate that oxygen fraction greater than ~0.5 produces undoped p-type ZnO films, whereas oxygen fraction less than ~0.5 produces undoped n-type ZnO films. This is attributed to the fact that the oxygen vacancies ($V_o$) decrease and the oxygen interstitials ($O_i$) or zinc vacancies ($V_{Zn}$) increase with increasing oxygen atoms incorporated into ZnO films during deposition and $O_2$ post-annealing.

• Transactions on Electrical and Electronic Materials
• /
• v.9 no.2
• /
• pp.67-72
• /
• 2008

Al-doped p-type ZnO thin films were fabricated by RF magnetron sputtering on n-Si (100) and homo-buffer layers in pure oxygen ambient. ZnO ceramic mixed with 2 wt% $Al_2O_3$ was selected as a sputtering target. XRD spectra show that the Al-doped ZnO thin films have ZnO crystal structure. Hall Effect experiments with Van der Pauw configuration show that p-type carrier concentrations are arranged from $1.66{\times}10^{16}$ to $4.04{\times}10^{18}\;cm^{-2}$, mobilities from 0.194 to $198\;cm^2V{-1}s^{-1}$ and resistivities from 0.0963 to $18.4\;{\Omega}cm$. FESEM cross section images of different parts of a p-type ZnO:Al thin film annealed at $800^{\circ}C$ show a compact structure. Measurement for same sample shows that density is $5.40\;cm^{-3}$ which is smaller than theoretically calculated value of $5.67\;cm^{-3}$. Photoluminescence (PL) spectra at 10 K show a shoulder peak of p-type ZnO film at about 3.117 eV which is ascribed to electron transition from donor level to acceptor level (DAP).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.7
• /
• pp.611-617
• /
• 2006

We report the preparation of N doped, p-type ZnO films by post-annealing in $NH_3$ ambient. The properties were examined by XRD, Hall-effect measurement, PL, and SIMS. ZnO films showed better crystallinity and electron concentration of $10^{15}-10^{17}/cm^3$ with post-annealing in $NH_3$ ambient. These films were converted to p-type ZnO by activation thermal annealing process at $800^{\circ}C$ under $N_2$ ambient. The electrical properties of the p-type ZnO showed a hole concentration of $1.06\times10^{16}/cm^3$, a mobility of $15.8cm^2/V{\cdot}s$, and a resistivity of $40.18\Omega{\cdot}cm$. The N doped ZnO films showed a strong photoluminescence peak at 3.306 eV at 13 K, which is closely related to neutral acceptor bound excitons of the p-type ZnO:N. In the SIMS spectra, the incorporation of nitrogen was confirmed.

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

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

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