• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
• /
• pp.51-53
• /
• 2005

$Zn_{1-x}Cd_xO$ thin films were grown on (0001) sapphire substrates by pulsed laser deposition. The energy bandgap of $Zn_{1-x}Cd_xO$ films decreases withincreasing Cd content. An increase of Cd content also leads to the emission broadening and degraded crystallinity. The absorption edge and ultraviolet emission peak shift to lower energy from 3.357 eV to 3.295 eV and 3.338 eV to 3.157 eV, respectively, with increasing Cd content from 0.3% to 3%. The Stokes' shift between the absorption and emission indicates the increase of localization of exciton with Cd content.

• 한국전기전자재료학회논문지
• /
• 제36권1호
• /
• pp.74-80
• /
• 2023

Gallium oxide (Ga₂O₃) thin films were grown on c-, a-, m-, r-plane sapphire substrates using a mist chemical vapor deposition system. Various growth temperature range of 400~600℃ was applied for Ga₂O₃ thin film deposition. Then, several structural properties were characterized such as film thickness, crystal phase, lattice orientation, surface roughness, and optical bandgap. Under the certain growth temperature of 500℃, all grown Ga₂O₃ featured rhombohedral crystal structures and well-aligned preferred orientation to sapphire substrate. The films grown on c-and r-plane sapphire substrates, showed low surface roughness and large optical bandgap compared to those on a-and m-plane substrates. Therefore, various sapphire orientation can be potentially applicable for future Ga₂O₃-based electronics applications.

• 한국전기전자재료학회논문지
• /
• 제23권4호
• /
• pp.280-286
• /
• 2010

We have investigated the influence of rapid thermal annealing (RTA) temperature on properties of Al-doped zinc oxide (AZO) thin films deposited on glass substrate by using radio-frequency magnetron sputtering. The RTA is performed in a nitrogen ambient in the temperature range from 300 to $600^{\circ}C$ for 1 minute in a rapid thermal annealer after growing the AZO thin films. The crystallographic structure and the surface morphology of AZO thin film are measured by using X-ray diffraction, and atomic force microscopy and scanning electron microscopy, respectively. The optical transmittance of the deposited thin films is examined in the wavelength range of 300-1100 nm, where the average transmittance is above the 90% in the visible and near-infrared regions. The optical bandgap is calculated from the Tauc's model, and it shows a significant dependence on the RTA temperature. As for the electrical properties of the thin films, the AZO thin film annealed at $400^{\circ}C$ shows the lowest electrical resistivity of $8.6{\times}10^{-3}{\Omega}cm$ and the Hall mobility of $11.3cm^2$/V-sec. These results suggest that the RTA temperature is an important parameter to influence on the structural, electrical, and optical properties of AZO thin films.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.248.2-248.2
• /
• 2014

In this study, the optical properties and structural characteristics of gallium nitride (GaN) thin films prepared by radio frequency (RF) magnetron sputtering were investigated. Auger electron and X-ray photoelectron spectra showed that the deposited films consisted mainly of gallium and nitrogen. The presence of oxygen was also observed. The optical bandgap of the GaN films was measured to be approximately 3.31 eV. The value of the refractive index of the GaN films was found to be 2.36 at a wavelength of 633 nm. X-ray diffraction data revealed that the crystalline phase of the deposited GaN films changed from wurtzite to zinc-blende phase upon decreasing the sputtering gas pressure. Along with the phase change, a strong dependence of the microstructure of the GaN films on the sputtering gas pressure was also observed. The microstructure of the GaN films changed from a voided columnar structure having a rough surface to an extremely condensed structure with a very smooth surface morphology as the sputtering gas pressure was reduced. The relationship between the phase and microstructure changes in the GaN films will be discussed.

• 한국표면공학회지
• /
• 제41권4호
• /
• pp.129-133
• /
• 2008

Nitrogen and aluminum codoped ZnO(NAZO) thin films were grown on glass substrates with changing the nitrogen flow ratio by radio-frequency magnetron sputtering. The structural, optical, and electrical properties of the NAZO films were investigated. The surface morphologies and the structural properties of the thin films were analyzed by using the X-ray diffraction and scanning electron microscopy. The NAZO thin film, deposited at nitrogen flow ratio of 0%, showed a strongly c-axis preferred orientation and the lowest resistivity of $3.2{\times}10^{-3}{\Omega}cm$. The intensity of ZnO(002) diffraction peak was decreased gradually with increasing the nitrogen flow ratio. The optical properties of the films were measured by UV-VIS spectrophotometer and the optical transmittances for all the samples were found to be an average 90% in the visible range. Based on the transmittance value, the optical bandgap energy for the NAZO thin film deposited at nitrogen flow ratio of 0% was determined to be 3.46 eV. As for the electrical properties, the carrier concentration and the hall mobility were decreased, but the electrical resistivity was increased as the nitrogen flow ratio was increased.

• Current Photovoltaic Research
• /
• 제5권4호
• /
• pp.113-121
• /
• 2017

The researches on the silicon-based thin films are being actively carried out. The silicon-based thin films can be made as amorphous, microcrystalline and mixed phase and it is known that the optical bandgap can be controlled accordingly. They are suitable materials for the fabrication of single junction, tandem and triple junction solar cells. It can be used as a doping layer through the bonding of boron and phosphorus. The carbon and oxygen can bond with silicon to form a wide range of optical gap. Also, The optical gap of hydrogenated amorphous silicon germanium can be lower than that of silicon. By controlling the optical gaps, it is possible to fabricate multi-junction thin film silicon solar cells with high efficiencies which can be promising photovoltaic devices.

• ETRI Journal
• /
• 제13권4호
• /
• pp.70-79
• /
• 1991

$In_1-x$$GA_X$$As_y$$P_1-y$ has a very wide range of applications in optoelectronic devices especially for optical communications because $In_1-x$$GA_X$$As_y$$P_1-y$ has the bandgap of the lowest dispersion ($1.3\mum$) and the lowest loss ( $1.55\mum$) of the optical fiber by changing the composition. The quality of $In_1-x$$GA_X$$As_y$$P_1-y$ epitaxial layer is believed to have a significant effect on the performance of device. The OMVPE growth conditions for the latticematched $In_1x$$GA_X$$As_y$$P_1-y$/InP were investigated. Effects of growth conditions such as V/III ratio, growth temperature, and Ga source material on the electrical and optical properties were studied. The composition, electrical and optical properities of $In_1-x$$GA_X$$As_y$$P_1-y$ were characterized using double crystal X-ray diffractometer (DCD), photoluminescence (PL), XPS(ESCA) and Hall measurement.

• 한국전기전자재료학회논문지
• /
• 제24권3호
• /
• pp.177-181
• /
• 2011

We have studied structural, optical, and electrical properties of the Al-doped ZnO (AZO) thin films being usable in transparent conducting oxides. The AZO thin films were deposited on the corning 1737 glass plate by the RF magnetron sputtering system. To find optimal properties of AZO for transparent conducting oxides, the RF power in sputtering process was varied as 40 W, 60 W, and 80 W, respectively. As RF power increased, the crystallinity of AZO thin film was decreased, the optical bandgap of AZO thin film increased. The transmittance of the film was over 80% in the visible light range regardless of the changes in RF power. The measurement of Hall effect characterizes the whole thin film as n-type, and the electrical property was improved with increasing RF power. The structural, optical, and electrical properties of the AZO thin films were affected by Al dopant content in AZO thin film.

• 한국전기전자재료학회논문지
• /
• 제31권3호
• /
• pp.177-181
• /
• 2018

We prepared ZnS thin films via chemical bath deposition (CBD) in an aqueous solution of ammonia ($NH_3$) and hydrazine ($N_2H_4$). The composition ratio of hydrazine used was 0%, 17%, 22%, 29%, or 50%. We investigated the effects of hydrazine and ammonia on the growth, and the structural and optical properties of ZnS in terms of surface uniformity, voids, and grain size. We found that during the growth of ZnS films, hydrazine was very effective for improving the surface morphology and layer uniformity with fast layer formation, while it had no effect on the bandgap energy, $E_g$.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
• /
• pp.332-334
• /
• 1995

In this paper, structual, optical properties of CdTe thin films and photovoltaic properties of thin film CdS/CdTe solar cell prepared by thermal vacuum evaporation were studied. The crystal structure of CdTe films was zircblend type with preferential orientation of the (111)plane parallel to the substrate. The heat treatment appears to stabilize this structure. The result of optical absorption and transmittance show that solar radiation with energy larger than bandgap is almost completely absorbed within an about $2{\mu}m$ thickness of the evaporated CdTe layer and transmittance of the CdTe film was larger with increasing annealing temperature. It was found that CdS/CdTe solar cell characteristics were improved by the heat treatment.