Influence of the crosstalk on the intensity of HAADF-STEM images of quaternary semiconductor materials

The influence of the neighbouring atomic-columns in determining the composition at atomic column scale of quaternary semiconductor compounds, using simulated HAADF-STEM images is evaluated. The InAlAsSb alloy, a promising material in the photovoltaic field, is considered. We find that the so called ‘crosstalk’ effect plays an important role for the aimed compositional determination. The intensity transfer is larger from neighbouring atomic columns with higher average Z, and towards atomic columns with smaller Z. Our results show that in order to obtain precise information on the column composition, the HAADF-STEM intensities of both columns need to be taken into account simultaneously.     

基于异质结倍增层的InAlAsSb SACM雪崩光电二极管的优化

使用低工作电压的雪崩光电二极管(APD)有利于提高集成电路的稳定性和降低功耗.文章建立了一个分离吸收、电荷、倍增(SACM)型的雪崩光电二极管的模型,为了在低偏压下获得高增益同时不降低工作电压范围,这个模型采用了具有高低禁带宽度的异质结倍增层.同时,文章研究了异质结倍增层的厚度和掺杂浓度对暗电流和增益的影响.通过对掺杂浓度的优化,击穿电压和穿通电压可以同时下降.