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1 – 3 of 3Ying Wei, Xueyuan Cai, Jinzhi Ran and Jianhong Yang
The purpose of this paper is to investigate the dependence of dark current on threading dislocations (TDs) in relaxed Ge layer for Ge/Si heterojunction photodetectors.
Abstract
Purpose
The purpose of this paper is to investigate the dependence of dark current on threading dislocations (TDs) in relaxed Ge layer for Ge/Si heterojunction photodetectors.
Design/methodology/approach
The analysis of the effects of TDs is based on SRH generation and recombination mechanism used in two‐dimensional drift‐diffusion numerical simulation.
Findings
It is found that the TDs in Ge layer acting as the recombination centers lead to large dark current densities of devices, and the recombination rate is affected by the impurity out‐diffusion from Si substrate. Besides, the TDs, being the acceptor‐like defects simultaneously, form band barrier at Si/Ge interface with lightly doped Si substrates, thus limiting the minority carrier transport and resulting in low dark current densities.
Originality/value
The simulation results are excellently consistent with the experimental data and indicate that the reduction of threading dislocation densities (TDDs), especially in Ge buffer layer, dramatically decreases dark currents densities of Ge/Si photodetectors. The investigation can be applied to imbue devices with desired characteristics.
Details
Keywords
Jian‐hong Yang, Ying Wei, Xue‐yuan Cai and Jin‐zhi Ran
The paper aims to investigate the influences of the tensile strain and the threading dislocations (TDs) in the germanium (Ge) epitaxial layer on the performance of the Ge vertical…
Abstract
Purpose
The paper aims to investigate the influences of the tensile strain and the threading dislocations (TDs) in the germanium (Ge) epitaxial layer on the performance of the Ge vertical p‐i‐n photodetectors on Si substrate.
Design/methodology/approach
The dark current, photo responsivity and time responsivity of detector were calculated using two‐dimensional drift‐diffusion device modeling and compared with experimental data.
Findings
The incorporation of the tensile strain and the reduction of the TDs in the Ge epilayer can increase the performance of the detector.
Originality/value
An optical design of detector is suggested with lower TD in the Ge buffer layer, which can exhibit superior performance.
Details