title: Suppression of dark current in germanium-tin on silicon p-i-n photodiode by a silicon surface passivation technique.
abstract: We demonstrate that a complementary metal-oxide-semiconductor (CMOS) compatible silicon (Si) surface passivation technique effectively suppress the dark current originating from the mesa sidewall of the Ge(0.95)Sn(0.05) on Si (Ge(0.95)Sn(0.05)/Si) p-i-n photodiode. Current-voltage (I-V) characteristics show that the sidewall surface passivation technique could reduce the surface leakage current density (Jsurf) of the photodiode by ~100 times. A low dark current density (Jdark) of 0.073 A/cm(2) at a bias voltage of -1 V is achieved, which is among the lowest reported values for Ge(1-x)Sn(x)/Si p-i-n photodiodes. Temperature-dependent I-V measurement is performed for the Si-passivated and non-passivated photodiodes, from which the activation energies of dark current are extracted to be 0.304 eV and 0.142 eV, respectively. In addition, the optical responsivity of the Ge(0.95)Sn(0.05)/Si p-i-n photodiodes to light signals with wavelengths ranging from 1510 nm to 1877 nm is reported.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Dong
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Dian
authors.initials: D
authors.lastname: Lei
authors.forename: Xiao
authors.initials: X
authors.lastname: Gong
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.forename: Shuh Ying
authors.initials: SY
authors.lastname: Lee
authors.forename: Wan Khai
authors.initials: WK
authors.lastname: Loke
authors.forename: Soon-Fatt
authors.initials: SF
authors.lastname: Yoon
authors.forename: Eng Soon
authors.initials: ES
authors.lastname: Tok
authors.forename: Gengchiau
authors.initials: G
authors.lastname: Liang
authors.forename: Yee-Chia
authors.initials: YC
authors.lastname: Yeo