Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.

The embodiments of the present disclosure describe a stressed Ge PD and fabrications techniques for making the same. In one embodiment, a stressor material is deposited underneath an already formed Ge PD. To do so, wafer bonding can be used to bond the wafer containing the Ge PD to a second, handler wafer. Doing so provides support to remove the substrate of the wafer so that a stressor material (e.g., silicon nitride, diamond-like carbon, or silicon-germanium) can be disposed underneath the Ge PD. The stress material induces a stress or strain in the crystal lattice of the Ge which changes its bandgap and improves its responsivity.

The embodiments of the present disclosure describe a stressed Ge PD and fabrications techniques for making the same. In one embodiment, a stressor material is deposited underneath an already formed Ge PD. To do so, wafer bonding can be used to bond the wafer containing the Ge PD to a second, handler wafer. Doing so provides support to remove the substrate of the wafer so that a stressor material (e.g., silicon nitride, diamond-like carbon, or silicon-germanium) can be disposed underneath the Ge PD. The stress material induces a stress or strain in the crystal lattice of the Ge which changes its bandgap and improves its responsivity.

A multijunction solar cell includes a base substrate comprising a Group IV semiconductor and a dopant of a first carrier type. A patterned emitter is formed at a first surface of the base substrate. The patterned emitter comprises a plurality of well regions doped with a dopant of a second carrier type in the Group IV semiconductor. The base substrate including the patterned emitter form a first solar subcell. The multijunction solar cell further comprises an upper structure comprising one or more additional solar subcells over the first solar subcell. Methods of making a multijunction solar cell are also described.

Structures for a photodetector and methods of fabricating a structure for a photodetector. The structure includes a light-absorbing region having a side edge, an anode adjacent to the side edge of the light-absorbing region, and a cathode adjacent to the side edge of the light-absorbing region.

Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.

The invention relates to a light-emitting component comprising a light-emitting section consisting of a Hex-Si.sub.1−xGe.sub.x compound material, said Hex-Si.sub.1−xGe.sub.x compound material having a direct band gap for emitting light.

The invention also pertains to a light-absorbing component comprising a light-absorbing section consisting of a Hex-S.sub.1−xGe.sub.x compound material, said Hex-Si.sub.1−xGe.sub.x compound material having a direct band gap for absorbing light.

A germanium based avalanche photo-diode device and method of manufacture thereof. The device including: a silicon substrate; a lower doped silicon region, positioned above the substrate; a silicon multiplication region, positioned above the lower doped silicon region; an intermediate doped silicon region, positioned above the silicon multiplication region; a doped germanium interface layer, positioned above the intermediate doped silicon region; an un-doped germanium absorption region, position above the doped germanium interface layer; an upper doped germanium region, positioned above the un-doped germanium absorption region; and an input silicon waveguide; wherein: the un-doped germanium absorption region and the upper doped germanium region form a germanium waveguide which is coupled to the input waveguide, and the device also includes a first electrode and a second electrode, and the first electrode extends laterally to contact the lower doped silicon region and the second electrode extends laterally to contact the upper doped germanium region.

Germanium (Ge)-Silicon (Si) structures, optoelectronic devices and method for forming same. A structure comprises a Si substrate, a Ge seed layer and a Ge epitaxial layer separated by respective interfaces that share a common plane normal, wherein the Si substrate and the Ge seed layer have a same first doping type with a first doping level, and a locally doped region formed in the Si layer adjacent to the Ge seed layer and having a second doping type with a second doping level, wherein the locally doped region is designed to reduce leakage currents between the Si substrate and the Ge epitaxial layer when an electrical bias is applied to the structure.

Various embodiments of the present disclosure are directed towards an image sensor with a passivation layer for dark current reduction. A device layer overlies a substrate. Further, a cap layer overlies the device layer. The cap and device layers and the substrate are semiconductor materials, and the device layer has a smaller bandgap than the cap layer and the substrate. For example, the cap layer and the substrate may be silicon, whereas the device layer may be or comprise germanium. A photodetector is in the device and cap layers, and the passivation layer overlies the cap layer. The passivation layer comprises a high k dielectric material and induces formation of a dipole moment along a top surface of the cap layer.