Dark current analysis of germanium-on-insulator vertical p-i-n photodetectors with varying threading dislocation density

Abstract

Dark current analysis of germanium-on-insulator vertical p-i-n photodetectors with varying threading dislocation density

Simulation of High-Efficiency Resonant-Cavity-Enhanced GeSn Single-Photon Avalanche Photodiodes for Sensing and Optical Quantum Applications

“…where C is a material parameter, which is related to trap capture cross-section, carrier thermal velocity and number of traps per unit length of dislocation. Since there is few study on GeSn, we use results for Ge photodiodes [34] to extract the parameter C, which is estimated to be 0.19 cm 2 /s. Additionally, the correction term 𝛤𝛤 accounting for the field-effect of TAT is given by Hurkx's model [35].…”

High Performance p-i-n Photodetectors on Ge-on-Insulator Platform

“…In ref [17], the leakage current of Ge p-i-n photodiodes on a GOI substrate with threading dislocation density (TDD) of~3.2 × 10 6 cm −2 was reduced by 53-fold from one with a TDD of~5.2 × 10 8 cm −2 . In addition, the introduction of an insulator layer between the Si and Ge can provide better optical confinement for the Ge active layer, enhancing the optical responses of the devices [18].…”

“…During the preparation of GOI substrates, the low-temperature Ge layer with high defect density was removed, resulting in fewer generation/recombination centers in the Ge crystal [ 16 ]. In ref [ 17 ], the leakage current of Ge p-i-n photodiodes on a GOI substrate with threading dislocation density (TDD) of ~3.2 × 10 6 cm −2 was reduced by 53-fold from one with a TDD of ~5.2 × 10 8 cm −2 . In addition, the introduction of an insulator layer between the Si and Ge can provide better optical confinement for the Ge active layer, enhancing the optical responses of the devices [ 18 ].…”

Dark current in monolithic extended-SWIR GeSn PIN photodetectors

“…The lattice mismatch between Ge and GeSn layers creates misfits and threading dislocations, which are the main reason for the high dark current [17][18][19][20] . However, studies of the dominating leakage mechanisms and the non-radiative carrier lifetime in GeSn PIN photodetectors remain conspicuously missing in literature despite their crucial importance to the development of all-group IV e-SWIR technologies.…”

“…According to PL measurements (not shown) the effective bandgap for the GeSn device is 0.52 eV (2.4 µm) 12 . Generally, the dark current generation in PIN device is attributed to three main mechanisms 18,27 : (1) diffusion leakage current due to the minority carriers at the edges of the depletion region, which corresponds to an activation energy (E a ) close the bandgap energy (∼ 0.52 eV);…”