共查询到20条相似文献,搜索用时 15 毫秒
1.
为了制备结晶质量好的Cu掺杂ZnO薄膜,研究其结构和光学性质,采用脉冲激光沉积方法,在Si衬底上选择不同的衬底温度来制备薄膜。实验成功制得了结晶质量较好的Cu掺杂ZnO薄膜。利用X射线衍射仪、扫描电子显微镜和荧光分光光度计对样品进行了测量和分析。所制备的样品均表现出高度的c轴择优取向,衬底温度为300℃时,薄膜表面形貌均匀致密;在样品的光致发光谱中,发现样品除了在380nm附近出现紫外发光峰外,在460nm附近出现了蓝光发光峰,真正意义上实现了ZnO薄膜的蓝光发射。结果表明,衬底温度对其晶体质量有较大影响。 相似文献
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Characteristics of Ga-doped ZnO films deposited by pulsed DC magnetron sputtering at low temperature
Kyung-Jun Ahn Sanghun Lee Won-Jeong Kim Geun Young Yeom Woong Lee 《Materials Science in Semiconductor Processing》2013,16(6):1957-1963
Characteristics of Ga-doped ZnO (GZO) transparent conductive oxide films have been investigated based on the absorption behavior and chemical states of dopant Ga in the film. GZO samples were prepared by pulsed DC magnetron sputtering at 423 K by varying the sputtering power from 0.6 to 2.4 kW and the Ga2O3 concentration in the targets from 0.6 to 5.7 wt%. Absorption spectra of the GZO films in the visible to ultraviolet range were characterized by long absorption tails and shoulders near the absorption edges indicating the presence of impurity states or bands that overlap with the conduction band. X-ray photoelectron spectroscopy and X-ray diffraction revealed that substantial portion of the dopant exists as finely dispersed or amorphous metallic Ga and oxide of Ga, which would be related to the formation of the impurity bands or states, especially in the samples with lower Ga content. Presence of these species is correlated to the limited doping efficiency observed in the GZO films. 相似文献
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Jin Hyung Jun Kyungah Cho Junggwon Yun Kwang S. Suh TaeYoung Kim Sangsig Kim 《Organic Electronics》2008,9(4):445-451
Polyaniline nanofibers embedded with undoped ZnO nanoparticles (NPs) or Ga-doped ZnO (ZnO:Ga) NPs were fabricated and their structural and electrical properties were investigated. The uniform distribution of the NPs inside the polyaniline nanofibers was confirmed by transmission electron microscopy analysis. Polyaniline nanofibers embedded with ZnO:Ga-NPs showed their higher conductivities, compared with polyaniline nanofibers embedded with undoped ZnO-NPs. Single nanofibers electrospun from a mixture of a polyaniline solution with a 30 vol% ZnO:Ga-NPs dispersed-solution showed approximately five times higher conductivity than those electrospun from the polyaniline solution alone. This observation indicates that the embedding of the ZnO:Ga-NPs significantly enhances the electrical characteristics of the polyaniline nanofibers. 相似文献
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J. Petersen M. Gallart G. Schmerber B. Hönerlage J.L. Rehspringer S. Colis A. Dinia 《Microelectronics Journal》2009,40(2):239-241
The present study focused on ZnO thin films fabricated by sol-gel process and spin coated onto Si (1 0 0) and quartz substrates. ZnO thin films have a hexagonal würtzite structure with a grain diameter about 50 nm. Optical properties were determined by photoluminescence (PL) and absorption spectroscopy. The absorption spectrum is dominated by a sharp excitonic peak at room and low temperatures. At room temperature, two transitions were observed by PL. One near to the prohibited energy band in ultraviolet (UV) region and the other centered at 640 nm, characteristic of the electronic defects in the band-gap. The spectrum at 6 K is dominated by donor-bound exciton lines and donor-acceptor pair transition. LO-phonon replica and two-electron satellite transitions are also observed. These optical characteristics are a signature of high-quality thin films. 相似文献
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Optical characteristics of twisted nematic liquid-crystal films 总被引:1,自引:0,他引:1
A twisted nematic liquid crystal is shown by theory and experiment to rotate incident plane-polarised light by ?/2 only at specified wavelengths. At other wavelengths, elliptically polarised light is produced. This action determines the contrast ratio of some twisted nematic devices. 相似文献
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Sachin D. Kshirsagar M. Ghanashyam Krishna Surya P. Tewari 《Materials Science in Semiconductor Processing》2013,16(3):1002-1007
The growth of wurtzite ZnTe thin films with thickness between 250 and 1000 nm on borosilicate glass substrates by electron beam evaporation is reported. The formation of the wurtzite structure was confirmed using X-ray diffraction. The films showed diffraction peaks originating from the (110), (016) and (116) planes, indicating absence of any preferred orientation. The transmission of all the films was of the order of 80% in the near IR region. The refractive index of the wurtzite ZnTe phase increased with increase in thickness from 3.0 at 250 nm to 4.2 for the 1000 nm thickness film at a wavelength of 1800 nm. The optical band gap of these films increased with thickness showing values of 0.85, 0.9 and 0.98 eV at 250, 400 and 1000 nm thickness, respectively. Chemical composition studies revealed that the films were mildly non-stoichiometric with excess Te. Comparison with the zinc blende structure of ZnTe shows that the wurtzite structure has a higher refractive index, lower band gap and lower charge carrier concentration. 相似文献
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An 8 μ m thick Ga-doped ZnO (GZO) film grown by metal-source vapor phase epitaxy was deposited on a GaN-based light-emitting diode (LED) to substitute for the conventional ITO as a transparent conduct layer (TCL). Electroluminescence spectra exhibited that the intensity value of LED emission with a GZO TCL is markedly improved by 23.6% as compared to an LED with an ITO TCL at 20 mA. In addition, the forward voltage of the LED with a GZO TCL at 20 mA is higher than that of the conventional LED. To investigate the reason for the increase of the forward voltage, X-ray photoelectron spectroscopy was performed to analyze the interface properties of the GZO/p-GaN heterojunction. The large valence band offset (2.24± 0.21 eV) resulting from the formation of Ga2O3 in the GZO/p-GaN interface was attributed to the increase of the forward voltage. 相似文献
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An 8 μm thick Ga-doped ZnO (GZO) film grown by metal-source vapor phase epitaxy was deposited on a GaN-based light-emitting diode (LED) to substitute for the conventional ITO as a transparent conduct layer (TCL). Electroluminescence spectra exhibited that the intensity value of LED emission with a GZO TCL is markedly improved by 23.6% as compared to an LED with an ITO TCL at 20 mA. In addition, the forward voltage of the LED with a GZO TCL at 20 mA is higher than that of the conventional LED. To investigate the reason for the increase of the forward voltage, X-ray photoelectron spectroscopy was performed to analyze the interface properties of the GZO/p-GaN heterojunction. The large valence band offset (2.24±0.21 eV) resulting from the formation of Ga2O3 in the GZO/p-GaN interface was attributed to the increase of the forward voltage. 相似文献
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The electrical characteristics of Pd Schottky contacts on ZnO films have been investigated by current-voltage (I–V) and capacitance–voltage (C–V) measurements at different temperatures. ZnO films of two thicknesses (400 nm and 1000 nm) were grown by DC-magnetron sputtering on n-Si substrates. The basic structural, optical and electrical properties of these films are also reported. We compared the two Schottky diodes by means of characteristic parameters, such as rectification ratio, ideality factor (η), barrier height (Φb) and series resistance and obtained better results for the 1000 nm-ZnO Schottky diodes. We also discussed the dependence of I‐V characteristics on temperature and the two distinct linear regions observed at low temperatures are attributed to the existence of two different inhomogeneous barrier heights. From I–V plots in a log-log scale we found that the dominant current-transport mechanism at large forward bias is space-charge limited current (SCLC) controlled by the presence of traps within the ZnO bandgap. The existence of such traps (deep states or interface states) is demonstrated by frequency-dependent capacitance and deep-level transient spectroscopy (DLTS) measurements. 相似文献
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The hydrogen gas sensing properties of highly Ga-doped ZnO (GZO) polycrystalline thin films deposited by radio-frequency magnetron sputtering have been studied. The relationship between the microstructural properties of preferred c-axis oriented thin films and the hydrogen gas sensing properties is described. The crystallite size and the preferred orientation distribution were characterized by X-ray diffraction. The crystallite size increased and the preferred orientation distribution decreased with increasing film thickness. In order to control the crystallite size and the c-axis orientation separately, a highly oriented ZnO template layer with different thickness was employed for deposition of 30-nm-thick GZO films. The c-axis orientation of these films were nearly comparable each other, while the crystallite size increased significantly with increasing thickness of the ZnO templates. The hydrogen gas sensitivity at an operating temperature of 330 °C increased slightly with decreasing crystallite size, while the sensitivity was dramatically enhanced by increasing the preferred orientation distribution. It is therefore proposed that the c-axis orientation plays an important role in determining the sensitivity of the hydrogen gas sensor. 相似文献
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利用直流磁控溅射工艺,在水冷玻璃衬底上成功沉积出了高透光、低电阻率的Ti-Al共掺ZnO(TAZO)透明导电薄膜.X射线衍射(XRD)研究结果表明,TAZO薄膜为具有c轴择优取向的六角纤锌矿结构多品薄膜.研究了TAZO薄膜的应力、结构以及光电性能与薄膜厚度的关系,结果表明.当薄膜厚为531 nm时,薄膜晶格畸变最小,具... 相似文献
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《Microelectronic Engineering》2006,83(2):328-335
This study examined the plasma etching characteristics of ZnO thin films etched in BCl3/Ar, BCl3/Cl2/Ar and Cl2/Ar plasmas with a positive photoresist mask. The ZnO etch rates were increased in a limited way by increasing the gas flow ratio of the main etch gases in the BCl3/Ar, BCl3/Cl2/Ar and Cl2/Ar plasmas at a fixed dc self-bias voltage (Vdc). However, the ZnO etch rate was increased more effectively by increasing the Vdc. Optical emission spectroscopy (OES) and X-ray photoelectron spectroscopy (XPS) analyses of the ZnO surfaces etched at various Cl2/(Cl2 + Ar) mixing ratios revealed the formation of the ZnOxCly reaction by-products as a result of the increased etch rate with increasing Cl2 addition, compared with 100% Ar+ sputter etching. This suggests that at Cl2/Ar flow ratios ⩾20%, the ZnO etch process is controlled by an ion-assisted removal mechanism where the etch rate is governed by the ion-bombardment energy under the saturated chlorination conditions. 相似文献
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《Materials Science in Semiconductor Processing》2012,15(1):80-85
This work considers a Mn-doped ZnO (ZnO:Mn) film deposited on a slide glass substrate by ultrasonic spray pyrolysis. ZnO:Mn (Mn at 1.5 at%) film with and without an applied magnetic field, is demonstrated to have absorption edges at 2.74 and 2.84 eV, respectively. These values are lower than that of a pure ZnO film because the Mn-doping causes the exchange of s–d and p–d interactions or high carrier concentration. When the ZnO:Mn film is placed in a magnetic field Bz of 0.5 T, an absorption edge and a photoluminescence (PL) shift of about 0.1 eV and 85 meV, respectively, are observed. This shift is attributed to the interband magneto-optic absorption associated with the Landau splitting. The observed shift increases with the amount of Mn dopant. 相似文献
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采用直流反应磁控溅射法在Si衬底上引入ZnO缓冲层制备了沿(200)晶面择优取向生长的MgO薄膜,然后分别采用快速退火和常规退火两种不同的方式对MgO薄膜进行晶化处理。利用X射线衍射仪(XRD)以及原子力显微镜(AFM)研究了ZnO缓冲层以及两种不同的退火方式对MgO薄膜的结构和形貌的影响。结果表明:具有合适厚度的ZnO缓冲层可以显著地提高MgO薄膜的结晶质量。另外,与快速退火相比,常规退火处理后得到的MgO晶粒均匀圆润,有着较大的(200)衍射峰强度以及较小的表面粗糙度。 相似文献
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ZnO/diamond-like carbon(DLC)thin films are deposited by pulsed laser deposition(PLD),and the room-temperature photoluminescence(PL)is investigated.Using a fluorescence spectrophotometer,we obtain the PL spectra of DLC/Si and ZnO/Si thin films deposited at different substrate temperatures.The ZnO/DLC thin films show a broadband emission almost containing the entire visible spectrum.The Gaussian fitting curves of PL spectra reveal that the visible emission of ZnO/DLC thin films consists of three peaks centered at 381 nm,526 nm and 682 nm,which are attributed to the radiative recombination of ZnO and DLC,respectively.The Commission International de l,Eclairage(CIE)1931(x,y)chromaticity space of ZnO/DLC thin films indicates that the visible PL spectrum is very close to the standard white-light region. 相似文献
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In the present study, a simple method for the preparation of a luminescent flexible gallium doped zinc oxide (GZO)/polystyrene nanocomposite film was developed. The prepared GZO powder was characterized through different optical and structural techniques. The XRD study revealed the existence of a wurtzite structure with no extra oxide peaks. Elemental-mapping, EDX, FTIR and XPS analyses were used to confirm the presence of elements and the several groups present in the structure. Under excitations of UV, the prepared hybrid nanocomposite showed a strong cyan emission with narrow full width at half the maximum value (20 nm) that has not been reported before. X-ray and laser-induced luminescence results of the hybrid film revealed novel blue-green emission at room temperature. The prepared composite film showed a strong scintillation response to ionizing radiation. The strong emissions, very weak deep-level emissions, and low FWHM of composite indicate the desirable optical properties with low-density structural defects in the GZO composite structure. Therefore, the prepared hybrid film can be considered to be a suitable candidate for the fabrication of optoelectronic devices. 相似文献
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S. G. Dorofeev N. N. Kononov A. A. Ishchenko R. B. Vasil’ev M. A. Goldschtrakh K. V. Zaitseva V. V. Koltashev V. G. Plotnichenko O. V. Tikhonevich 《Semiconductors》2009,43(11):1420-1427
A new technique of growing nanocrytalline silicon (nc-Si) thin films is suggested. The technique involves the centrifuge-assisted size-selective deposition of nanoparticles from a colloidal solution (sol) containing nc-Si powders. The structural and optical parameters of the initial nc-Si powders and films deposited by the newly suggested procedure are studied by transmission electron microscopy and analysis of absorption spectra and Raman spectra. The absorption coefficient of the nc-Si films increases with decreasing dimensions of the constituent nanoparticles. The experimentally measured band gap of the films, E g, is widened from 1.8 to 2.2. eV on etching the nc-Si powders used for deposition of the corresponding films. On the basis of the analysis of the Raman spectra, it is suggested that the amorphous component is involved in the nc-Si powders and films due to oxygen atoms arranged at the nanoparticle surface. 相似文献