High-performance long-lifetime charge-separation photodetectors are provided. A new device design is described based on novel band structure engineering of semiconductor materials for photodetectors, such as photosensors, solar cells, and thermophotovoltaic devices. In an exemplary aspect, photodetectors described herein include a charge-separated photo absorber region. This comprises a semiconductor with a band structure that has an indirect fundamental bandgap, with a direct bandgap (┌-┌ transition) only slightly above the indirect fundamental bandgap (L- or X-┌ transitions) (e.g., approximately equal to or larger than an energy of a product of the Boltzmann constant (k.sub.B), and temperature (T), with k.sub.BT=26 millielectron-volts (meV) at room temperature). This design not only improves photogenerated-carrier lifetime (similar to indirect bandgap semiconductors), but also maintains a strong absorption coefficient (similar to direct bandgap semiconductors).

An integrated optical sensor is formed by a pinned photodiode. A semiconductor substrate includes a first semiconductor region having a first type of conductivity located between a second semiconductor region having a second type of conductivity opposite to the first type one and a third semiconductor region having the second type of conductivity. The third semiconductor region is thicker, less doped and located deeper in the substrate than the second semiconductor region. The third semiconductor region includes both silicon and germanium. In one implementation, the germanium within the third semiconductor region has at least one concentration gradient. In another implementation, the germanium concentration within the third semiconductor region is substantially constant.

Monolithic pixel detectors, systems and methods for the detection and imaging of electromagnetic radiation with high spectral and spatial resolution comprise a Si wafer with a CMOS processed pixel readout bonded to an absorber wafer in wafer bonds comprising conducting bonds between doped, highly conducting charge collectors in the readout and highly conducting regions in the absorber wafer and poorly conducting bonds between regions of high resistivity.

A ultraviolet detector includes a substrate; a first epitaxial layer that is a heavily doped epitaxial layer and located on the substrate, a second epitaxial layer located on the first epitaxial layer, where the second epitaxial layer is a lightly doped epitaxial layer, or a double-layer or multi-layer structure composed of at least one lightly doped epitaxial layer and at least one heavily doped epitaxial layer; an ohmic contact layer located on the second epitaxial layer or formed in the second epitaxial layer, where the ohmic contact layer is a graphical heavily doped layer; and a first metal electrode layer located on the ohmic contact layer.

Structures including multiple photodiodes and methods of fabricating a structure including multiple photodiodes. A substrate has a first trench extending to a first depth into the substrate and a second trench extending to a second depth into the substrate that is greater than the first depth. A first photodiode includes a first light-absorbing layer containing a first material positioned in the first trench. A second photodiode includes a second light-absorbing layer containing a second material positioned in the second trench. The first material and the second material each include germanium.

The disclosure is related to the technical field of semiconductors, and provides a method for manufacturing a tilted mesa and a method for manufacturing a detector. The method for manufacturing a tilted mesa comprises: coating a photoresist layer on a mesa region of a chip; heating the chip on which the photoresist layer is coated from a first preset temperature to a second preset temperature; performing etching processing on the heated chip, so as to manufacture a mesa having a preset tilting angle; and removing the photoresist layer on the mesa region of the chip after the mesa is manufactured.

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.

Low noise silicon-germanium (SiGe) image sensor. In one embodiment, an image sensor includes a plurality of pixels arranged in rows and columns of a pixel array disposed in a semiconductor substrate. The photodiodes of an individual pixel are configured to receive an incoming light through an illuminated surface of the semiconductor substrate. The semiconductor substrate includes a first layer of semiconductor material having silicon (Si); and a second layer of semiconductor material having silicon germanium (Si1-xGex). A concentration x of Ge changes gradually through at least a portion of thickness of the second layer. Each photodiode includes a first doped region extending through the first layer of semiconductor material and the second layer of semiconductor material; and a second doped region extending through the first layer of semiconductor material and the second layer of semiconductor material.

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.