Photocurrent saturation and negative differential photoconductivity in Mn_4Si_7-Si〈Mn〉-Mn_4Si_7 and Mn_4Si_7-Si〈Mn〉-M heterojunctions

摘要

A mechanism behind the saturation of the photocurrent and occurrence of negative differential photoconductivity in Mn_4Si_7-Si〈Mn〉-Mn_4Si_7 and Mn_4Si_7-Si〈Mn〉-M heterojunctions is found. Mn_4Si_7-Si〈Mn〉-Mn_4Si_7 and Mn_4Si_7-Si〈Mn〉-M structures are studied with a model of back-to-back diodes. Photocurrent-voltage characteristics are taken at high constant and pulsed applied biases. It is found that the nonlinearity of the photocurrent-voltage characteristics and photoconductivity kinetics are due to the quenching of photoconductivity by Joule self-heating.