Cover Picture: High quantum efficiency UV detection using a-Se based photodetector (Phys. Status Solidi RRL 7/2013)
Tomoaki Masuzawa, Masanori Onishi, Ichitaro Saito, Takatoshi Yamada, Angel T. T. Koh, Daniel H. C. Chua, Shuichi Ogawa, Yuji Takakuwa, Yusuke Mori, Tatsuo Shimosawa and Ken Okano
Version of Record online: 15 JUL 2013 | DOI: 10.1002/pssr.201370438
Multiplication in the bulk: Photo-generated elec-tron–hole pairs are split and accelerated in amorphous selenium bulk, which trigger carrier multiplication generating extra carriers. This carrier multiplication boosts the signal of a photodetector, allowing ultra high-sensitivity photodetection. The sensitivity of a prototype photodetector, evaluated in terms of external quantum efficiency, is up to 1,000 for ultraviolet light (∼375 nm), which suggests that up to 1,000 carriers are generated per incident photon. In the Letter by Masuzawa et al. (see pp. 473–476), the physics of the carrier multiplication has been investigated in terms of current–voltage characteristics of the prototype photodetector.