Photodetectors, methods of fabricating the same, and methods using the same to detect radiation are described. A photodetector can include a first electrode, a light sensitizing layer, an electron blocking/tunnelling layer, and a second electrode. Infrared-to-visible upconversion devices, methods of fabricating the same, and methods using the same to detect radiation are also described. An Infrared-to-visible upconversion device can include a photodetector and an OLDE coupled to the photodetector.

An encapsulated integrated photodetector waveguide structures with alignment tolerance and methods of manufacture are disclosed. The method includes forming a waveguide structure bounded by one or more shallow trench isolation (STI) structure(s). The method further includes forming a photodetector fully landed on the waveguide structure.

Photodiode structures and methods of manufacture are disclosed. The method includes forming a waveguide structure in a dielectric layer. The method further includes forming a Ge material in proximity to the waveguide structure in a back end of the line (BEOL) metal layer. The method further includes crystallizing the Ge material into a crystalline Ge structure by a low temperature annealing process with a metal layer in contact with the Ge material.

A Ge-on-Si photodetector constructed without doping or contacting Germanium by metal is described. Despite the simplified fabrication process, the device has responsivity of 1.24 A/W, corresponding to 99.2% quantum efficiency. Dark current is 40 nA at 4 V reverse bias. 3-dB bandwidth is 30 GHz.

A temperature-controlled photodetector sub-system is described. The temperature control element allows the operation of the photodetector at a desired temperature. The temperature control element can be a heater or a cooler. In some cases, the photodetector is a germanium photodetector. In some cases a temperature measuring device is provided. In some cases, a control circuit is used to control the temperature of the germanium photodetector within a temperature range, or at a temperature of interest. An advantage provided by the apparatus described is the operation of the photodetector so that the responsivity of the germanium detector can be held at essentially a constant value.

A method of making a germanium perovskite/crystalline germanium thin-film tandem solar cell including the steps of depositing a textured oxide buffer layer on glass, depositing a SnGe film from a eutectic alloy on the buffer layer; and depositing perovskite elements on the SnGe film, thus forming a perovskite layer based on the Ge from the SnGe film, incorporating the Ge into the perovskite layer.

Some embodiments include a semiconductor device. The semiconductor device includes a transistor having a gate metal layer, a transistor composite active layer, and one or more contact elements over the transistor composite active layer. The transistor composite active layer includes a first active layer and a second active layer, the first active layer is over the gate metal layer, and the second active layer is over the first active layer. Meanwhile, the semiconductor device also includes one or more semiconductor elements forming a diode over the transistor. The semiconductor element(s) have an N-type layer over the transistor, an I layer over the N-type layer, and a P-type layer over the I layer. Other embodiments of related systems and methods are also disclosed.

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as pillars and/or holes, effectively increase the effective absorption length resulting in a greater absorption of the photons. Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s at photons with wavelengths of 850 nm, and with quantum efficiencies of approximately 90% or more.

Examples of the various techniques introduced here include, but not limited to, a mesa height adjustment approach during shallow trench isolation formation, a transistor via first approach, and a multiple absorption layer approach. As described further below, the techniques introduced herein include a variety of aspects that can individually and/or collectively resolve or mitigate one or more traditional limitations involved with manufacturing PDs and transistors on the same substrate, such as above discussed reliability, performance, and process temperature issues.

A performance of a semiconductor device is improved. In a method of manufacturing a semiconductor device, a first semiconductor portion and a second semiconductor portion made of silicon are formed on a base body via an insulation layer, and a third semiconductor portion including a semiconductor layer made of germanium is formed on the second semiconductor portion. Next, an insulation film is formed above the first semiconductor portion, an opening portion reaching the first semiconductor portion from an upper surface of the insulation film is formed, and a metal silicide layer is formed on a part of an upper surface of the first semiconductor portion exposed to the opening portion.