飞行时间二次离子质谱仪(Time of flight secondary ion mass spectrometry,TOF-SIMS)对所有元素具有极高的检测灵敏度,应用此方法研究了经550℃退火处理,Au/AuBe/Au与GaP金属-半导体的各元素强度分布特性,依次分析金属表面、金属层内...飞行时间二次离子质谱仪(Time of flight secondary ion mass spectrometry,TOF-SIMS)对所有元素具有极高的检测灵敏度,应用此方法研究了经550℃退火处理,Au/AuBe/Au与GaP金属-半导体的各元素强度分布特性,依次分析金属表面、金属层内、金属-半导体界面、半导体内部,使用O2+正离子与Cs+负离子分析Au、Be、O、Ga、P五类元素在各层内的强度,观察金属层与半导体界面内Be、O、Au、P峰位置的各元素SIMS图,表明在金属表面3~10nm内含有Au、Be、O、Ga、P元素,在金属内部,O元素在AuBe层有明显分布,在半导体材料GaP层内含有Be、Au元素,且Be的扩散深度比Au要深,在AuBe层及界面处用XPS分析化学组分。展开更多
研究了n型Au/GaN肖特基势垒紫外光探测器的电子辐照失效机理。从实验中观测到,随着电子辐照注量的不断增加,Au/GaN间辐照诱生的界面态引起器件的击穿电压明显减小,反向漏电流逐渐增大。辐照诱生的深能级缺陷导致紫外光探测器对较长波长...研究了n型Au/GaN肖特基势垒紫外光探测器的电子辐照失效机理。从实验中观测到,随着电子辐照注量的不断增加,Au/GaN间辐照诱生的界面态引起器件的击穿电压明显减小,反向漏电流逐渐增大。辐照诱生的深能级缺陷导致紫外光探测器对较长波长光的吸收,使得UV探测器中可见光成分的背景噪声增加。同时,对辐照后的 GaN 肖特基紫外光探测器进行了100℃以下的退火处理,退火后,器件的电流 电压特性有所改善。展开更多
In this work, we investigate the Co-Si reaction, the Co growth mode at room temperature, diffusion be- haviour as well as morphology evolution during annealing on both H-terminated and clean Si(001) and Si(111) sur- f...In this work, we investigate the Co-Si reaction, the Co growth mode at room temperature, diffusion be- haviour as well as morphology evolution during annealing on both H-terminated and clean Si(001) and Si(111) sur- faces. From in-situ X-ray photoelectron spectroscopy (XPS) investigation, “Co-Si” reaction appears to occur on both H-terminated and clean surfaces at room temperature (RT) and the silicide crystallinity is improved upon annealing. Co growth mode on H-terminated Si surfaces occurs in a pseudo layer-by-layer manner while small close-packed is- land growth mode is observed on the clean Si surface. Upon annealing at different temperatures, Co atom concentra- tion decreases versus annealing time, which in part is attributed to Co atoms inward diffusion. The diffusion behav- iour on both types of surfaces demonstrates a similar trend. Morphology study using ex-situ atomic force microscopy (AFM) shows that the islands formed on Si(001) surface after annealing at 700 °C are elongated with growth direc- tions alternate between the two perpendicular [ 110 ] and [110] directions. Triangular islands are observed on Si (111) surface.展开更多
Phonon modes of AlAs/GaAs/AlAs and GaAs/AlAs/metal Pb quantum-dot quantum wells (QDQW's)with the whole scale up to 90 A are calculated by using valence force field model (VFFM) based on group theory.Their optical ...Phonon modes of AlAs/GaAs/AlAs and GaAs/AlAs/metal Pb quantum-dot quantum wells (QDQW's)with the whole scale up to 90 A are calculated by using valence force field model (VFFM) based on group theory.Their optical frequency spectra are divided into two nonoverlapping bands, the AMs-like band and the GaAs-like band,originated from and having frequency interval inside the bulk AlAs optical band and bulk GaAs optical band, respectively.The GaAs-LO (F)-like modes of QDQW's that have maximum bulk GaAs-LO (F) parentages in all modes covering the whole frequency region and all symmetries have always A1 symmetry. Its frequency is controllable by adjusting the structure parameters. In AlAs/GaAs/AlAs, it may be controlled to meet any designed frequency in GaAs-like band.The results on GaAs/AMs/metal Pb QDQW's show the same effect of reducing in interface optical phonons by using the metal/semiconductor interface revealed ever by macroscopic model. The frequency spectra in both GaAs-like and AlAs-like optical phonon bands are independent of the thickness of Pb shell as long as the thickness of Pb shell is no less than 5 A. Defects at metal/AlAs interface have significant influence to AMs-like optical modes but have only minor influence to GaAs-like optical modes. All these results are important for the studying of the e-ph interaction in QD structures.展开更多
文摘飞行时间二次离子质谱仪(Time of flight secondary ion mass spectrometry,TOF-SIMS)对所有元素具有极高的检测灵敏度,应用此方法研究了经550℃退火处理,Au/AuBe/Au与GaP金属-半导体的各元素强度分布特性,依次分析金属表面、金属层内、金属-半导体界面、半导体内部,使用O2+正离子与Cs+负离子分析Au、Be、O、Ga、P五类元素在各层内的强度,观察金属层与半导体界面内Be、O、Au、P峰位置的各元素SIMS图,表明在金属表面3~10nm内含有Au、Be、O、Ga、P元素,在金属内部,O元素在AuBe层有明显分布,在半导体材料GaP层内含有Be、Au元素,且Be的扩散深度比Au要深,在AuBe层及界面处用XPS分析化学组分。
文摘研究了n型Au/GaN肖特基势垒紫外光探测器的电子辐照失效机理。从实验中观测到,随着电子辐照注量的不断增加,Au/GaN间辐照诱生的界面态引起器件的击穿电压明显减小,反向漏电流逐渐增大。辐照诱生的深能级缺陷导致紫外光探测器对较长波长光的吸收,使得UV探测器中可见光成分的背景噪声增加。同时,对辐照后的 GaN 肖特基紫外光探测器进行了100℃以下的退火处理,退火后,器件的电流 电压特性有所改善。
文摘In this work, we investigate the Co-Si reaction, the Co growth mode at room temperature, diffusion be- haviour as well as morphology evolution during annealing on both H-terminated and clean Si(001) and Si(111) sur- faces. From in-situ X-ray photoelectron spectroscopy (XPS) investigation, “Co-Si” reaction appears to occur on both H-terminated and clean surfaces at room temperature (RT) and the silicide crystallinity is improved upon annealing. Co growth mode on H-terminated Si surfaces occurs in a pseudo layer-by-layer manner while small close-packed is- land growth mode is observed on the clean Si surface. Upon annealing at different temperatures, Co atom concentra- tion decreases versus annealing time, which in part is attributed to Co atoms inward diffusion. The diffusion behav- iour on both types of surfaces demonstrates a similar trend. Morphology study using ex-situ atomic force microscopy (AFM) shows that the islands formed on Si(001) surface after annealing at 700 °C are elongated with growth direc- tions alternate between the two perpendicular [ 110 ] and [110] directions. Triangular islands are observed on Si (111) surface.
文摘Phonon modes of AlAs/GaAs/AlAs and GaAs/AlAs/metal Pb quantum-dot quantum wells (QDQW's)with the whole scale up to 90 A are calculated by using valence force field model (VFFM) based on group theory.Their optical frequency spectra are divided into two nonoverlapping bands, the AMs-like band and the GaAs-like band,originated from and having frequency interval inside the bulk AlAs optical band and bulk GaAs optical band, respectively.The GaAs-LO (F)-like modes of QDQW's that have maximum bulk GaAs-LO (F) parentages in all modes covering the whole frequency region and all symmetries have always A1 symmetry. Its frequency is controllable by adjusting the structure parameters. In AlAs/GaAs/AlAs, it may be controlled to meet any designed frequency in GaAs-like band.The results on GaAs/AMs/metal Pb QDQW's show the same effect of reducing in interface optical phonons by using the metal/semiconductor interface revealed ever by macroscopic model. The frequency spectra in both GaAs-like and AlAs-like optical phonon bands are independent of the thickness of Pb shell as long as the thickness of Pb shell is no less than 5 A. Defects at metal/AlAs interface have significant influence to AMs-like optical modes but have only minor influence to GaAs-like optical modes. All these results are important for the studying of the e-ph interaction in QD structures.
