Journal of the Chinese Institute of Electrical Engineering(J. Chinese Institute of Electrical Engineering)
摘要:本論文針對低溫成長砷化鎵光致電導閥所產生電脈衝在高偏壓時常見的緩慢下降 之來源做一研究。我們系統的比較各種基座及間隙寬度之光致電導閥，並藉由砷化鎵中電場 強度之計算，我們發現此緩慢下降之產生與消耗之功率關係並不強烈。藉此除去光致電 導閥下半絕緣砷化鎵基座，我們發現即可除去這些在高偏壓時常見之緩慢下降；由此，我們 提出一新的模型以解說此現象：這些在高偏壓時常見之緩下降乃由在基座中所產生的光激載 子之位移電流所造成。因此欲除去這些在高偏壓時常見之緩慢下降必須使用透明或不吸收光 的基座。 Abstract:The origin of the long trailing shoulders observed from photoconductive switches fabricated on low-temperature-grown GaAs at high bias voltage was studies. By a comparative study of the photoconductive switches fabricated on LT-GaAs on different substrated and with different gapwidths, we found that the dependence of the trailing shoulders on the power dissipation is weak. Comparing the calculated electric fields at various depths in photoconductive switches with different gapwidths, we proposed that the long trailing tails should result mainly from the photo-carriers generated deep in the substrate; these carries, though blocked by the AlAs layer,can modify the electric field distribution in the LT-GaAs layer, leading to a displacement current component. Our model was corroborated by the great reduction of the long trailing tails with the elimination of the SI GaAs substrate underneath the photoconductive swithch.