Transmission and emission characteristics of porous silicon in terahertz from 0.5T to 10T

摘要

In order to develop silicon-based modulation or emission materials, silicones covered by porous silicon (ps) thin film were characterized about terahertz transmission and emission properties from 0.5T to 10T frequency by THz Time Domain spectrograph. Ps films were etched different morphologies through hydrothermal method. According to SEM, micro-surface-structures of these ps films were divided into three types: crater, quasi nano-pillar-array and porous. Terahertz wave transmission amplitude of cater samples was decreased largest and its transmission time delay was the least among the three samples. Compare to cater sample, THz transmission intensity of quasi-nano-pillar sample increased 27%, porous one increased 53%. For time delay, quasi-nano-pillar sample was 0.04ps, porous one was 0.3ps. The first two type's samples had low-pass characteristics and porous samples had cascade band-pass characteristic. There were much absorption peaks in the spectrum of quasi nano-pillar-array sample and porous one. Positions of these peaks had very closed relationship to the micro-surface-structures of ps thin films. In addition, samples could generate μW THz emission at 10THz area after excitation by femtosecond laser. Experiments showed that, both shape and size of these ps films appeared to change and control transmission and emission properties of silicon in 0.5T to 10T, such as transmitted intensity, absorption frequency and emission properties, so nano-micro system porous silicon could be considered as a new material for THz modulation, emission and it could be applied to make integration wide-spectral device.? (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.