Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize th...Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize the effect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP （O-ICP）＇s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP （CI-ICP）, the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP＇s treatment, while the work function after Cl-ICP＇s treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more effective than CI-ICP for enhancing the work function of AZO films, which is well consistent with KP results.展开更多
We report a back-gated metal-oxide-ferroelectric-metal （MOFM） field-effect transistor （FET） with lead zirconate titanate （PZT） material, in which an Al doped zinc oxide （AZO） channel layer with an optimized do...We report a back-gated metal-oxide-ferroelectric-metal （MOFM） field-effect transistor （FET） with lead zirconate titanate （PZT） material, in which an Al doped zinc oxide （AZO） channel layer with an optimized doping concentration of 1% is applied to reduce the channel resistance of the channel layer, thus guaranteeing a large enough load capacity of the transistor. The hysteresis loops of the Pt/PZT/AZO/Ti/Pt capacitor are measured and compared with a Pt/PZT/Pt capacitor, indicating that the remnant polarization is almost 40 μC/cm^2 and the polarization is saturated at 20 V. The measured capacitance-voltage properties are analyzed as a result of the electron depletion and accumulation switching operation conducted by the modulation of PZT on AZO channel resistance caused by the switchable remnant polarization of PZT. The switching properties of the AZO channel layer are also proved by the current-voltage transfer curves measured in the back-gated MOFM ferroelectric FET, which also show a drain current switching ratio up to about 100 times.展开更多
This study deals with the optimization of direct current（DC） sputtered aluminum-doped zinc oxide （AZO） thin films and their incorporation into a-Si：H/μc-Si：H tandem junction thin film solar cells aiming for hig...This study deals with the optimization of direct current（DC） sputtered aluminum-doped zinc oxide （AZO） thin films and their incorporation into a-Si：H/μc-Si：H tandem junction thin film solar cells aiming for high conversion efficiency.Electrical and optical properties of AZO films,i.e.mobility,carrier density,resistivity, and transmittance,were comprehensively characterized and analyzed by varying sputtering deposition conditions, including chamber pressure,substrate temperature,and sputtering power.The correlations between sputtering processes and AZO thin film properties were first investigated.Then,the AZO films were textured by diluted hydrochloric acid wet etching.Through optimization of deposition and texturing processes,AZO films yield excellent electrical and optical properties with a high transmittance above 81%over the 380-1100 nm wavelength range,lowsheet resistance of 11Ω/□and high haze ratio of 41.3%.In preliminary experiments,the AZO films were applied to a-Si：H/μc-Si：H tandem thin film solar cells as front contact electrodes,resulting in an initial conversion efficiency of 12.5%with good current matching between subcells.展开更多
Highly conductive and dispersible Al-doped ZnO(AZO) nanoparticles(NPs) have been successfully prepared by ligand-free colloidal synthesis at low temperature and stabilization by surfactant-aid including ethanolamine(E...Highly conductive and dispersible Al-doped ZnO(AZO) nanoparticles(NPs) have been successfully prepared by ligand-free colloidal synthesis at low temperature and stabilization by surfactant-aid including ethanolamine(EA), ethylenediamine(EDA),diethylenetriamine(DETA) and triethylenetetramine(TETA). Due to the strong intermolecular hydrogen-bonding interactions between AZO NPs and the amino groups from surfactants, the inevitable aggregation was suppressed and the surface defect sites were passivated obviously. The existence of electron transfer from the nitrogen of the amino groups to the zinc of AZO,led to a dramatic increase in electrical conductivity. A homogeneous current intensity value up to ~2200 pA for AZO tread by DETA was characterized by conductive atomic force microscopy(C-AFM), which was more superior than that of the reported sol-gel synthesized AZO with the assistance of EA surfactant(refer to 170.7 pA). Furthermore, non-fullerenes solar cells based on PBDB-T:ITIC with AZO-DETA(80 nm) yielded a best device efficiency of 10.7% and kept up prominent PCE exceeding 10%even with more thicker interlayer(95 nm).展开更多
A lossy mode resonance(LMR)-supported fiber optic sensor in which a uniform fiber core is placed among two identical tapered regions, is investigated numerically. Indium tin oxide(ITO)and aluminum-doped zinc oxide(AZO...A lossy mode resonance(LMR)-supported fiber optic sensor in which a uniform fiber core is placed among two identical tapered regions, is investigated numerically. Indium tin oxide(ITO)and aluminum-doped zinc oxide(AZO) are considered as LMR active materials used to excite several lossy modes and gold and silver are used as surface plasmon resonance(SPR) active materials. In this probe design, a central uniform core coated with ITO/AZO is the active sensing region, whereas tapered regions are meant for bringing the incident angle close to the critical angle. The sensitivity of the present fiber optic bio-sensor is evaluated for first two LMRs utilizing both ITO and AZO separately, along with its variation with the taper ratio(TR). For ITO, the maximum sensitivity values are observed to be 18.425 μm RIU^(-1)(refractive index unit)and 0.825 μm RIU^(-1), corresponding to the first and second LMRs, respectively, at a TR of 1.6 and for AZO, equivalent values are 0.79 μm RIU^(-1) and 0.35 μm RIU^(-1), respectively, at a TR of2.0. The results illustrate that the first LMR is more sensitive than the second LMR and the ITOcoated probe possesses greater sensitivity than the AZO-coated probe for both LMRs. Similarly,for the fiber optic SPR sensor, the maximum value of sensitivity is 5.6425 μm RIU^(-1), in the case of gold and 5.0615 μm RIU^(-1) in the case of silver, at a TR of 1.6. Hence, the result shows that the sensor with the present fiber optic probe design has around a 3-fold enhancement in sensitivity compared with conventional SPR sensors. This study will have applications in many sensing schemes where the requirement of large sensitivity is vital.展开更多
基金supported by National Natural Science Foundation of China(Nos.1100502151177017 and 11175049)+1 种基金the Fudan University Excellent Doctoral Research Program(985 Project) the Ph.D Programs Foundation of Ministry of Education of China(No.20120071110031)
文摘Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize the effect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP （O-ICP）＇s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP （CI-ICP）, the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP＇s treatment, while the work function after Cl-ICP＇s treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more effective than CI-ICP for enhancing the work function of AZO films, which is well consistent with KP results.
基金Supported by the Fundamental Research Funds for the Central Universities of China
文摘We report a back-gated metal-oxide-ferroelectric-metal （MOFM） field-effect transistor （FET） with lead zirconate titanate （PZT） material, in which an Al doped zinc oxide （AZO） channel layer with an optimized doping concentration of 1% is applied to reduce the channel resistance of the channel layer, thus guaranteeing a large enough load capacity of the transistor. The hysteresis loops of the Pt/PZT/AZO/Ti/Pt capacitor are measured and compared with a Pt/PZT/Pt capacitor, indicating that the remnant polarization is almost 40 μC/cm^2 and the polarization is saturated at 20 V. The measured capacitance-voltage properties are analyzed as a result of the electron depletion and accumulation switching operation conducted by the modulation of PZT on AZO channel resistance caused by the switchable remnant polarization of PZT. The switching properties of the AZO channel layer are also proved by the current-voltage transfer curves measured in the back-gated MOFM ferroelectric FET, which also show a drain current switching ratio up to about 100 times.
文摘This study deals with the optimization of direct current（DC） sputtered aluminum-doped zinc oxide （AZO） thin films and their incorporation into a-Si：H/μc-Si：H tandem junction thin film solar cells aiming for high conversion efficiency.Electrical and optical properties of AZO films,i.e.mobility,carrier density,resistivity, and transmittance,were comprehensively characterized and analyzed by varying sputtering deposition conditions, including chamber pressure,substrate temperature,and sputtering power.The correlations between sputtering processes and AZO thin film properties were first investigated.Then,the AZO films were textured by diluted hydrochloric acid wet etching.Through optimization of deposition and texturing processes,AZO films yield excellent electrical and optical properties with a high transmittance above 81%over the 380-1100 nm wavelength range,lowsheet resistance of 11Ω/□and high haze ratio of 41.3%.In preliminary experiments,the AZO films were applied to a-Si：H/μc-Si：H tandem thin film solar cells as front contact electrodes,resulting in an initial conversion efficiency of 12.5%with good current matching between subcells.
基金supported by the National Natural Science Foundation of China (51603099, 51672121)the National Science Fund for Distinguished Young Scholars (51425304)
文摘Highly conductive and dispersible Al-doped ZnO(AZO) nanoparticles(NPs) have been successfully prepared by ligand-free colloidal synthesis at low temperature and stabilization by surfactant-aid including ethanolamine(EA), ethylenediamine(EDA),diethylenetriamine(DETA) and triethylenetetramine(TETA). Due to the strong intermolecular hydrogen-bonding interactions between AZO NPs and the amino groups from surfactants, the inevitable aggregation was suppressed and the surface defect sites were passivated obviously. The existence of electron transfer from the nitrogen of the amino groups to the zinc of AZO,led to a dramatic increase in electrical conductivity. A homogeneous current intensity value up to ~2200 pA for AZO tread by DETA was characterized by conductive atomic force microscopy(C-AFM), which was more superior than that of the reported sol-gel synthesized AZO with the assistance of EA surfactant(refer to 170.7 pA). Furthermore, non-fullerenes solar cells based on PBDB-T:ITIC with AZO-DETA(80 nm) yielded a best device efficiency of 10.7% and kept up prominent PCE exceeding 10%even with more thicker interlayer(95 nm).
基金the Department of Science and Technology (DST),INDIA for providing the INSPIRE fellowship (Registration No.-IF170543)。
文摘A lossy mode resonance(LMR)-supported fiber optic sensor in which a uniform fiber core is placed among two identical tapered regions, is investigated numerically. Indium tin oxide(ITO)and aluminum-doped zinc oxide(AZO) are considered as LMR active materials used to excite several lossy modes and gold and silver are used as surface plasmon resonance(SPR) active materials. In this probe design, a central uniform core coated with ITO/AZO is the active sensing region, whereas tapered regions are meant for bringing the incident angle close to the critical angle. The sensitivity of the present fiber optic bio-sensor is evaluated for first two LMRs utilizing both ITO and AZO separately, along with its variation with the taper ratio(TR). For ITO, the maximum sensitivity values are observed to be 18.425 μm RIU^(-1)(refractive index unit)and 0.825 μm RIU^(-1), corresponding to the first and second LMRs, respectively, at a TR of 1.6 and for AZO, equivalent values are 0.79 μm RIU^(-1) and 0.35 μm RIU^(-1), respectively, at a TR of2.0. The results illustrate that the first LMR is more sensitive than the second LMR and the ITOcoated probe possesses greater sensitivity than the AZO-coated probe for both LMRs. Similarly,for the fiber optic SPR sensor, the maximum value of sensitivity is 5.6425 μm RIU^(-1), in the case of gold and 5.0615 μm RIU^(-1) in the case of silver, at a TR of 1.6. Hence, the result shows that the sensor with the present fiber optic probe design has around a 3-fold enhancement in sensitivity compared with conventional SPR sensors. This study will have applications in many sensing schemes where the requirement of large sensitivity is vital.
