Photoelectric converting film stack type solid-state image pickup device

• US 20080135828A1
• Filed: 01/09/2008
• Published: 06/12/2008
• Est. Priority Date: 03/17/2004
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: Fukunaga, Toshiaki
• Granted Patent: US 7,476,904 B2
• Time in Patent Office: Days
• US Class Current: 257/12
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements

Abstract

A photoelectric converting film stack type solid-state image pickup device comprising: a semiconductor substrate in which a signal read circuit is formed; and at least one photoelectric converting film interposed between two electrode films, said at least one photoelectric converting film being stacked above the semiconductor substrate, wherein a signal corresponding to an intensity of incident light is read outside by the signal read circuit, the signal being generated by photoelectric conversion with the photoelectric converting film, wherein the photoelectric converting film comprises: a first layer comprising: an ultrafine particle including (i) a quantum dot contributing to the photoelectric conversion and (ii) a material having a band gap larger than that of the quantum dot, the quantum dot being coated with the material; and a hole transport layer stacked on the first layer.

Claims

1. A photoelectric converting film stack type solid-state image pickup device comprising:

a semiconductor substrate in which a signal read circuit is formed; and

at least one photoelectric converting film interposed between two electrode films, said at least one photoelectric converting film being stacked above the semiconductor substrate,

wherein a signal corresponding to an intensity of incident light is read outside by the signal read circuit, the signal being generated by photoelectric conversion with the photoelectric converting film,

wherein the photoelectric converting film comprises;

a first layer comprising;

an ultrafine particle including (i) a quantum dot contributing to the photoelectric conversion and (ii) a material having a band gap larger than that of the quantum dot, the quantum dot being coated with the material; and

a hole transport layer stacked on the first layer, wherein the first layer further comprises an electron transport layer, and the ultrafine particle is dispersed in the electron transport layer.

2. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 1, wherein the hole transport layer comprises a semiconductor having a bad gap larger than that of the quantum dot.

3. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 2, wherein the semiconductor of the hole transport layer is doped with an impurity.

4. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 1, wherein the hole transport layer comprises an organic film.

5. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 1, wherein the quantum dot comprises CdSe or CdS and the material coated on the quantum dot is ZnSe or ZnS.

6. The photoelectric converting film stack type solid-state image pickup device as claimed claim 1, wherein said at least one photoelectric converting film comprises three photoelectric converting film layers which are stacked through a transparent insulating film, each of said at least one photoelectric converting film being interposed between two transparent electrode films.

7. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 6, wherein an average particle diameter of the ultrafine particle in each of said photoelectric converting films is determined such that first one of the three photoelectric converting film layers has a light absorption maximum at a wavelength of 400 to 500 nm, second one of the three photoelectric converting film layers has a light absorption maximum at a wavelength of 500 to 560 nm, and third one of the three photoelectric converting film layers a light absorption maximum at a wavelength of 560 to 640 nm.

8. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 1, wherein said at least one photoelectric converting film comprises four photoelectric converting film layers which are stacked through a transparent insulating film, each of said at least one photoelectric converting film being interposed between two transparent electrode films.

9. The photoelectric converting film stack type solid-state image pickup device as claimed in claim 8, wherein an average particle diameter of the ultrafine particle in each of said photoelectric converting films is determined such that first one of the four photoelectric converting film layers has a light absorption maximum at a wavelength of 420 to 480 nm, second one of the four photoelectric converting film layers has a light absorption maximum at a wavelength of 480 to 520 nm, third one of the four photoelectric converting film layers a light absorption maximum at a wavelength of 520 to 560 nm, and fourth one of the four photoelectric converting film layers a light absorption maximum at a wavelength of 560 to 620 nm.

10. The photoelectric converting film stack-type solid-state image pickup device as claimed in claim 9, wherein a red color signal amount is determined by subtracting a second amount of signals detected by the second photoelectric converting film layer from a fourth amount of signals detected by the fourth photoelectric converting film layer.