A photodetector comprising a photoabsorber, comprising a doped semiconductor, a contact layer comprising a doped semiconductor and a barrier layer comprising a charge carrier compensated semiconductor, the barrier layer compensated by doping impurities such that it exhibits a valence band energy level substantially equal to the valence band energy level of the photo absorbing layer and a conduction band energy level exhibiting a significant band gap in relation to the conduction band of the photo absorbing layer, the barrier layer disposed between the photoabsorber and contact layers. The relationship between the photo absorbing layer and contact layer valence and conduction band energies and the barrier layer conduction and valance band energies is selected to facilitate minority carrier current flow while inhibiting majority carrier current flow between the contact and photo absorbing layers.

An imaging element which is formed by sequentially stacking at least an anode, an anode-side buffer layer, a photoelectric conversion layer, and a cathode, in which the anode-side buffer layer includes a material having structural formula

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in which thiophene and carbazole are combined.

An imaging element according to an embodiment of the present disclosure includes: a first electrode and a second electrode facing each other; and a photoelectric conversion layer including a p-type semiconductor and an n-type semiconductor, and provided between the first electrode and the second electrode, in which the photoelectric conversion layer has an exciton charge separation rate of 1×10.sup.10 s.sup.−1 to 1×10.sup.16 s.sup.−1 both inclusive in a p-n junction surface formed by the p-type semiconductor and the n-type semiconductors.

An imaging element according to an embodiment of the present disclosure includes: a first electrode and a second electrode facing each other; and a photoelectric conversion layer including a p-type semiconductor and an n-type semiconductor, and provided between the first electrode and the second electrode, in which the photoelectric conversion layer has an exciton charge separation rate of 1×10.sup.10 s.sup.−1 to 1×10.sup.16 s.sup.−1 both inclusive in a p-n junction surface formed by the p-type semiconductor and the n-type semiconductors.

An ink composition containing a P-type semiconductor material, an N-type semiconductor material and two or more solvents including a first solvent and a second solvent, wherein the total amount of the first solvent and the second solvent is 70% by weight or more with respect to 100% by weight of all the solvents contained in the ink composition; the boiling point of the first solvent is lower than the boiling point of the second solvent; the boiling point of the first solvent is 120° C. or more and 400° C. or less; and the hydrogen bond Hansen solubility parameter H1 (MPa.sup.0.5) of the first solvent and the hydrogen bond Hansen solubility parameter H2 (MPa.sup.0.5) of the second solvent are in the relation of 0.5≦(H2−H1)≦5.0.

A semiconductor device includes a semiconductor substrate a pixel region in which an APD is disposed, and a logic region different from the pixel region; a transistor which is disposed in the logic region and includes a sidewall made of an insulating material; an anti-reflective film which is disposed above a main surface of the semiconductor substrate in the pixel region and is made of the insulating material; and a first liner film which is disposed above the main surface of the semiconductor substrate in the logic region and is made of the insulating material. The anti-reflective film and the first liner film are integrally formed. The thickness of the anti-reflective film is larger than or equal to the sum of the thickness of the sidewall and the thickness of the first liner film.

A detection device includes a photodiode, and a thin-film transistor coupled to the photodiode. The thin-film transistor includes a semiconductor layer between a light-blocking layer and the photodiode, and an electrode layer between the semiconductor layer and the photodiode, and the electric layer includes a source electrode and a drain electrode of the thin-film transistor. The source electrode extends to a position facing the light-blocking layer with the semiconductor layer interposed therebetween.

A photoelectric conversion element according to an embodiment of the present disclosure includes: a first electrode; a second electrode opposed to the first electrode; and an organic photoelectric conversion layer provided between the first electrode and the second electrode and formed using a plurality of materials having average particle diameters different from each other, the plurality of materials including at least fullerene or a derivative thereof, and a particle diameter ratio, of a first material having a smallest average particle diameter among the plurality of materials with respect to a second material having a largest average particle diameter among the plurality of materials, is 0.6 or less.

An imaging device includes a plurality of light-receiving elements arranged in a two-dimensional matrix shape. Each of the light-receiving elements includes a first electrode, a photoelectric conversion layer, and a second electrode. The photoelectric conversion layer has a laminated structure in which a first compound semiconductor layer having a first conductivity type and a second compound semiconductor layer having a second conductivity type that is a reverse conductivity type to the first conductivity type are laminated from a side of the first electrode. The second compound semiconductor layer has been removed in a region between the light-receiving elements. The first electrode and the first compound semiconductor layer are shared by the light-receiving elements. An impurity concentration of a first compound semiconductor layer near the first electrode is lower than that of a first compound semiconductor layer near the second compound semiconductor layer.

An imaging device includes a plurality of light-receiving elements arranged in a two-dimensional matrix shape. Each of the light-receiving elements includes a first electrode, a photoelectric conversion layer, and a second electrode. The photoelectric conversion layer has a laminated structure in which a first compound semiconductor layer having a first conductivity type and a second compound semiconductor layer having a second conductivity type that is a reverse conductivity type to the first conductivity type are laminated from a side of the first electrode. The second compound semiconductor layer has been removed in a region between the light-receiving elements. The first electrode and the first compound semiconductor layer are shared by the light-receiving elements. An impurity concentration of a first compound semiconductor layer near the first electrode is lower than that of a first compound semiconductor layer near the second compound semiconductor layer.