Optical properties of Zn-diffused InP layers for the planar-type InGaAs/InP photodetectors

• Published in: Journal of semiconductors 2017-12, Vol.38 (12), p.56-61
• Main Authors: Chen, Guifeng, Wang, Mengxue, Yang, Wenxian, Tan, Ming, Wu, Yuanyuan, Dai, Pan, Huang, Yuyang, Lu, Shulong
• Format: Article
• Language: English
• ISSN: 1674-4926
• DOI: 10.1088/1674-4926/38/12/124004

Zn diffusion into InP was carried out ex-situ using a new Zn diffusion technique with zinc phosphorus particles placed around InP materials as zinc source in a semi-closed chamber formed by a modified diffusion furnace. The optical characteristics of the Zn-diffused InP layer for the planar-type InGaAs/InP PIN photodetectors grown by molecular beam epitaxy （MBE） has been investigated by photoluminescence （PL） measurements. The temperature-dependent PL spectrum of Zn-diffused InP samples at different diffusion temperatures showed that band-to-acceptor transition dominates the PL emission, which indicates that Zn was commendably diffused into InP layer as the acceptor. High quality Zn-diffused InP layer with typically smooth surface was obtained at 580 ℃for 10 min. Furthermore, more interstitial Zn atoms were activated to act as acceptors after a rapid annealing process. Based on the above Zn-diffusion technique, a 50μm planar-type InGaAs/InP PIN photodector device was fabricated and exhibited a low dark current of 7.73 pA under a reverse bias potential of -5 V and a high break- down voltage of larger than 41 V （1 〈 10μA）. In addition, a high responsivity of 0.81 A/W at 1.31/~m and 0.97 A/W at 1.55μm was obtained in the developed PIN photodetector.