PROJECT TITLE :

Tensile-Strained Mid-Infrared GeSn Detectors Wrapped in Si 3N 4 Liner Stressor: Theoretical Investigation of Impact of Device Architectures

ABSTRACT:

In this paper, we comparatively studied the energy band diagram and also the cutoff wavelength characteristics of germanium–tin (GeSn) fin and pillar array detectors wrapped in a Si 3N 4 liner stressor to unveil the impacts of tensile strain and device design in the absorption spectra of the devices. A massive tensile strain is introduced into GeSn devices by the enlargement of the Si 3N four liner stressor. Compared to the fin detector, a larger tensile volume strain is demonstrated within the GeSn pillar design. With the tensile strain induced by the Si 3N 4 liner stressor, the direct bandgap of GeSn is clearly shrinked by lowering the energy of the conduction band valley, that results in a vital extension of absorption edge in the GeSn detectors. Because the Si 3N 4 liner stressor releases internal stress and expands, the absorption edge of the tensile-strained Ge 0.90Sn 0.10 pillar array detector with the length of side of pillar of a hundred nm is extended to 4.35 . With further improvement, the tensile-strained GeSn pillar design with the Si 3N 4 liner stressor can be competitive for the applying in a pair of–five- mid-infrared spectra.