Image pickup element, stacked image pickup element, and solid image pickup apparatus
An image pickup element includes a photoelectric conversion section including a first electrode, a photoelectric conversion layer including an organic material, and a second electrode stacked on one another. Between the first electrode and the photoelectric conversion layer, an oxide semiconductor layer and an oxide film are formed from the first electrode side.
1. An image pickup element, comprising:
a photoelectric conversion section including a first electrode, a photoelectric conversion layer, and a second electrode stacked on one another,
wherein, immediately below the photoelectric conversion layer, an oxide film and an oxide semiconductor layer are formed from a photoelectric conversion layer side, and
wherein a value Conc H-1 of a concentration of hydrogen atoms in a portion of the oxide semiconductor layer near an interface between the oxide film and the oxide semiconductor layer is higher than a value Conc H-2 of a concentration of hydrogen atoms in a central portion of the oxide semiconductor layer along a thickness direction.
2. The image pickup element according to claim 1 , wherein
at least some elements included in the oxide film are different from elements included in the oxide semiconductor layer.
3. The image pickup element according to claim 1 , wherein,
assuming that E 2 denotes an energy average value at a maximum energy value of a conductance band of the oxide semiconductor layer and that E 1 denotes an energy average value at a maximum energy value of a conductance band of the oxide film,
E 1 −E 2 ≥−0.4 (eV) is satisfied.
4. The image pickup element according to claim 3 , wherein,
assuming that E 0 denotes an energy average value at a LUMO value for the photoelectric conversion layer,
E 0 −E 1 ≥−0.4 (eV) is satisfied.
5. The image pickup element according to claim 4 , wherein
E 0 ≥E 1 ≥E 2 is satisfied.
6. The image pickup element according to claim 1 , wherein,
assuming that E 4 denotes an energy average value at a minimum energy value for a valence band of the oxide film and that E 3 denotes an energy average value at a HOMO value for the photoelectric conversion layer,
E 3 −E 4 ≥−0.4 (eV) is satisfied.
7. The image pickup element according to claim 6 , wherein,
assuming that E 5 denotes an energy average value at a minimum energy value for a valence band of the oxide semiconductor layer,
E 4 −E 5 ≥−0.4 (eV) is satisfied.
8. The image pickup element according to claim 7 , wherein
E 3 ≥E 4 ≥E 5 is satisfied.
9. The image pickup element according to claim 1 , wherein
a material included in the oxide film includes a metal oxide.
10. The image pickup element according to claim 9 , wherein
the metal oxide includes at least one element selected from a group including tantalum, titanium, vanadium, niobium, tungsten, zirconium, hafnium, scandium, yttrium, lanthanum, gallium, and magnesium.
11. The image pickup element according to claim 10 , wherein
the oxide film includes an addition of at least one element selected from a group including silicon, tantalum, vanadium, niobium, tungsten, zirconium, hafnium, scandium, yttrium, lanthanum, gallium, magnesium, aluminum, strontium, germanium, hydrogen, carbon, and nitrogen, and wherein the at least one element of the oxide film is different from the at least one element included in the metal oxide.
12. The image pickup element according to claim 9 , wherein
the oxide film has a thickness equal to or larger than one atomic layer and equal to or smaller than 1×10 −7 m.
13. The image pickup element according to claim 1 , wherein
the oxide film includes a tunnel oxide film.
14. The image pickup element according to claim 13 , wherein
the tunnel oxide film includes at least one type of material selected from a group including SiO X , SiON, SiOC, and AlO Y .
15. The image pickup element according to claim 13 , wherein
the tunnel oxide film has a thickness equal to or larger than one atomic layer and equal to or smaller than 5×10 −9 m.
16. The image pickup element according to claim 1 , wherein
the oxide film includes a stacked structure of a film including a metal oxide and a tunnel oxide film.
17. An image pickup element, comprising:
a photoelectric conversion section including a first electrode, a photoelectric conversion layer, and a second electrode stacked on one another,
wherein, immediately below the photoelectric conversion layer, an oxide film and an oxide semiconductor layer are formed from a photoelectric conversion layer side, and
wherein, assuming that Conc H-1 denotes a value of a concentration of hydrogen atoms in a portion of the oxide semiconductor layer near a n interface between the oxide film and the oxide semiconductor layer and that Conc M-1 denotes a value of a concentration of atoms included in the oxide film in the portion of the oxide semiconductor layer near the interface between the oxide film and the oxide semiconductor layer, a n average change rate ΔConc H-1 of Conc H-1 toward a central portion along a thickness direction of the oxide semiconductor layer is larger than an average change rate ΔConc M-1 of Conc M-1 toward the central portion along the thickness direction of the oxide semiconductor layer.
18. The image pickup element according to claim 1 , wherein
charge generated in the photoelectric conversion layer migrates to the first electrode via the oxide film and the oxide semiconductor layer.
19. The image pickup element according to claim 18 , wherein
the charge includes electrons.
20. A stacked image pickup element comprising:
at least one image pickup element according to claim 1 .
21. A solid image pickup apparatus comprising:
a plurality of the image pickup elements according to claim 1 .
22. A solid image pickup apparatus comprising:
a plurality of the stacked image pickup elements according to claim 20 .
23. The image pickup element according to claim 17 , wherein at least some elements included in the oxide film are different from elements included in the oxide semiconductor layer.