Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching process...Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF_(4)/Ar ratio of 50:50 sccm. Regardless of the ratio of CF_(4) to Ar,the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF-4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication.展开更多
The investigation of the structure and thermoelectric properties of nanostructured solid solutions (Bi, Sb)2Te3 p-type has been carried out. The samples were obtained by grinding of original compositions in a planetar...The investigation of the structure and thermoelectric properties of nanostructured solid solutions (Bi, Sb)2Te3 p-type has been carried out. The samples were obtained by grinding of original compositions in a planetary ball mill and by spark plasma sintering (SPS). Initial powder has an average particle size of 10 - 12 nm according to transmission electron microscopy, and the size of the coherent scattering region (CSR) obtained by X-ray line broadening. During sintering at Ts = 250°C - 400°C, the grain size and CSR increased, which was associated with the processes of recrystallization. The maximum of size distribution of CSR shifts to larger sizes when Ts increases so that no broadening of X-ray lines at Ts = 400°C can take place. At higher Ts, the emergence of new nanograins is observed. The formation of nanograins is conditioned by reducing of quantity of the intrinsic point defects produced in the grinding of the source materials. The study of the electrical conductivity and the Hall effect in a single crystal allows to estimate the mean free path of the holes-L in the single crystal Bi0.5Sb1.5Te3 which at room temperature is 2 - 5 nm (it is much smaller than the dimensions of CSR in the samples). The method for evaluation of L in polycrystalline samples is proposed. At room temperature, L is close to the mean free path in single crystals. Scattering parameter holes in SPS samples obtained from the temperature dependence of the Seebeck coefficient are within the measurement error equal to the parameter of the scattering of holes in a single crystal. The figure of merit ZT of SPS samples as a function of composition and sintering temperature has been investigated. Maximum ZT, equal to 1.05 at room temperature, is obtained for the composition Bi0.4Sb1.6Te3 at Ts = 500°C and a pressure of 50 MPa. The causes of an apparent increase in thermoelectric efficiency are discussed.展开更多
The influence of perimeter effects on dark I-V characteristics of GaAs diode is investigated experimentally.The results indicate that the diodes with high energy states density will be more easily shorted than that wi...The influence of perimeter effects on dark I-V characteristics of GaAs diode is investigated experimentally.The results indicate that the diodes with high energy states density will be more easily shorted than that with low energy states density during alloying.The possibility of shunt short of GaAs diode increases with the decrease of the distance between the front contact and pn junction.The AlGaAs layers enhance the dark current.展开更多
In this paper,InGaAs p-i-n photodetectors(PDs)on an InP/SiO2/Si(InPOI)substrate fabricated by ion-slicing technology are demonstrated and compared with the identical device on a commercial InP substrate.The quality of...In this paper,InGaAs p-i-n photodetectors(PDs)on an InP/SiO2/Si(InPOI)substrate fabricated by ion-slicing technology are demonstrated and compared with the identical device on a commercial InP substrate.The quality of epitaxial layers on the InPOI substrate is similar to that on the InP substrate.The photo responsivities of both devices measured at 1.55μm are comparable,which are about 0.808-0.828 A W^(-1).Although the dark current of PD on the InPOI substrate is twice as high as that of PD on the InP substrate at 300 K,the peak detectivities of both PDs are comparable.In general,the overall performance of the InPOI-based PD is comparable to the InP-based PD,demonstrating that the ion-slicing technology is a promising route to enable the highquality Si-based InP platform for the full photonic integration on a Si substrate.展开更多
基金supported by the National Research Foundation (NRF) of Korea (Nos. 2018R1D1A1B07051429 and 2020R1G1A1102692)。
文摘Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF_(4)/Ar ratio of 50:50 sccm. Regardless of the ratio of CF_(4) to Ar,the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF-4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication.
文摘The investigation of the structure and thermoelectric properties of nanostructured solid solutions (Bi, Sb)2Te3 p-type has been carried out. The samples were obtained by grinding of original compositions in a planetary ball mill and by spark plasma sintering (SPS). Initial powder has an average particle size of 10 - 12 nm according to transmission electron microscopy, and the size of the coherent scattering region (CSR) obtained by X-ray line broadening. During sintering at Ts = 250°C - 400°C, the grain size and CSR increased, which was associated with the processes of recrystallization. The maximum of size distribution of CSR shifts to larger sizes when Ts increases so that no broadening of X-ray lines at Ts = 400°C can take place. At higher Ts, the emergence of new nanograins is observed. The formation of nanograins is conditioned by reducing of quantity of the intrinsic point defects produced in the grinding of the source materials. The study of the electrical conductivity and the Hall effect in a single crystal allows to estimate the mean free path of the holes-L in the single crystal Bi0.5Sb1.5Te3 which at room temperature is 2 - 5 nm (it is much smaller than the dimensions of CSR in the samples). The method for evaluation of L in polycrystalline samples is proposed. At room temperature, L is close to the mean free path in single crystals. Scattering parameter holes in SPS samples obtained from the temperature dependence of the Seebeck coefficient are within the measurement error equal to the parameter of the scattering of holes in a single crystal. The figure of merit ZT of SPS samples as a function of composition and sintering temperature has been investigated. Maximum ZT, equal to 1.05 at room temperature, is obtained for the composition Bi0.4Sb1.6Te3 at Ts = 500°C and a pressure of 50 MPa. The causes of an apparent increase in thermoelectric efficiency are discussed.
文摘The influence of perimeter effects on dark I-V characteristics of GaAs diode is investigated experimentally.The results indicate that the diodes with high energy states density will be more easily shorted than that with low energy states density during alloying.The possibility of shunt short of GaAs diode increases with the decrease of the distance between the front contact and pn junction.The AlGaAs layers enhance the dark current.
基金supported by the National Key R&D Program of China(2017YFE0131300)the National Natural Science Foundation of China(62174167,61874128)+4 种基金the Frontier Science Key Program of CAS(QYZDY-SSW-JSC032)the Key Research Project of Zhejiang Laboratory(2021MD0AC01)the Program of Shanghai Academic Research Leader(19XD1404600)K.C.Wong Education Foundation(GJTD-2019-11)NCBiR within the Polish-China(WPC/130/NIR-Si/2018)。
基金supported by the National Key Research and Development Program of China(Grant No.2017YFE0131300)the National Natural Science Foundation of China(Grant Nos.U1732268,61874128,11622545,61851406,11705262,61875220,and 61804157)+7 种基金the Frontier Science Key Program of Chinese Academy of Sciences(Grant Nos.QYZDY-SSWJSC032,and ZDBS-LY-JSC009)the Chinese-Austrian Cooperative Research and Development Project(Grant No.GJHZ201950)the Shanghai Science and Technology Innovation Action Plan Program(Grant No.17511106202)the Program of Shanghai Academic Research Leader(Grant No.19XD1404600)the Shanghai Youth Top Talent ProgramShanghai Sailing Program(Grant Nos.19YF1456200,and 19YF1456400)the K.C.Wong Education Foundation(Grant No.GJTD-2019-11)the NCBiR within the Polish-China(Grant No.WPC/130/NIR-Si/2018)。
文摘In this paper,InGaAs p-i-n photodetectors(PDs)on an InP/SiO2/Si(InPOI)substrate fabricated by ion-slicing technology are demonstrated and compared with the identical device on a commercial InP substrate.The quality of epitaxial layers on the InPOI substrate is similar to that on the InP substrate.The photo responsivities of both devices measured at 1.55μm are comparable,which are about 0.808-0.828 A W^(-1).Although the dark current of PD on the InPOI substrate is twice as high as that of PD on the InP substrate at 300 K,the peak detectivities of both PDs are comparable.In general,the overall performance of the InPOI-based PD is comparable to the InP-based PD,demonstrating that the ion-slicing technology is a promising route to enable the highquality Si-based InP platform for the full photonic integration on a Si substrate.
