Research on photo-generated carriers escape in PIN and NIN structures with quantum wells

Relevant experiments have shown that more than 90% of photo-generated carriers can escape from multiple quantum wells (MQWs) sandwiched between p-type and n-type layers (a PIN structure). The escape time of the photo-generated carriers is on the femtosecond scale, much less than their relaxation time. In contrast, photo-generated carriers cannot escape from MQWs sandwiched between two n-type layers (a NIN structure) with bias. We found that there is a high barrier for holes and that the electric field intensity in QWs is close to zero, resulting in holes accumulating and a low escape efficiency in a NIN structure with bias.