Optimizing Performance of Silicon-Based p–n Junction Photodetectors by the Piezo-Phototronic Effect

• Published in: ACS nano 2014-12, Vol.8 (12), p.12866-12873
• Main Authors: Wang, Zhaona, Yu, Ruomeng, Wen, Xiaonan, Liu, Ying, Pan, Caofeng, Wu, Wenzhuo, Wang, Zhong Lin
• Format: Article
• Language: English
• Subjects: Optoelectronic devices; Optoelectronics; P-n junctions; Photodetectors; Piezoelectricity; Semiconductors; Silicon; Zinc oxide
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/nn506427p

Silicon-based p–n junction photodetectors (PDs) play an essential role in optoelectronic applications for photosensing due to their outstanding compatibility with well-developed integrated circuit technology. The piezo-phototronic effect, a three-way coupling effect among semiconductor properties, piezoelectric polarizations, and photon excitation, has been demonstrated as an effective approach to tune/modulate the generation, separation, and recombination of photogenerated electron–hole pairs during optoelectronic processes in piezoelectric-semiconductor materials. Here, we utilize the strain-induced piezo-polarization charges in a piezoelectric n-ZnO layer to modulate the optoelectronic process initiated in a p-Si layer and thus optimize the performances of p-Si/ZnO NWs hybridized photodetectors for visible sensing via tuning the transport property of charge carriers across the Si/ZnO heterojunction interface. The maximum photoresponsivity R of 7.1 A/W and fastest rising time of 101 ms were obtained from these PDs when applying an external compressive strain of −0.10‰ on the ZnO NWs, corresponding to relative enhancement of 177% in R and shortening to 87% in response time, respectively. These results indicate a promising method to enhance/optimize the performances of non-piezoelectric semiconductor material (e.g., Si) based optoelectronic devices by the piezo-phototronic effect.