LIGHT-EMITTING DEVICE

• US 20110017996A1
• Filed: 09/15/2010
• Published: 01/27/2011
• Est. Priority Date: 11/10/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.), Japan Science & Technology Trading Co. Limited, Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.), Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Inventors: Kamiya, Toshio, Nomura, Kenji, Iwasaki, Tatsuya, Den, Tohru, Hosono, Hideo
• Granted Patent: US 8,212,252 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• CPC Class Codes: G03G 5/08 characterised by the photoconductive material being inorganic
• CPC Class Codes: G03G 5/144 comprising inorganic material
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]

Abstract

An Object of the Present Invention is to provide a new light-emitting device with the use of an amorphous oxide. The light-emitting device has a light-emitting layer existing between first and second electrodes and a field effect transistor, of which the active layer is an amorphous.

Claims

1. A light-emitting device having a light-emitting element comprising first and second electrodes and a light-emitting layer existing between the first and second electrodes, and a field effect transistor for driving the light-emitting element, wherein

the active layer of the field effect transistor is formed of an amorphous oxide having an electronic carrier concentration of less than 10¹⁸/cm³.

2. The light-emitting device according to claim 1, wherein the amorphous oxide includes at least one of In, Zn and Sn.

3. The light-emitting device according to claim 1, wherein the amorphous oxide is any one selected from the group consisting of an oxide containing In, Zn and Sn;

an oxide containing In and Zn;

an oxide containing In and Sn; and

an oxide containing In.

4. The light-emitting device according to claim 1, wherein the amorphous oxide includes In, Zn and Ga.

5. The light-emitting device according to claim 1, wherein the light-emitting element and the field effect transistor are arranged on an optically transparent substrate, and a light emitted from the light-emitting layer is output through the substrate.

6. The light-emitting device according to claim 5, wherein the field effect transistor is arranged between the substrate and the light-emitting layer.

7. The light-emitting device according to claim 1, wherein the light-emitting element and the field effect transistor are arranged on an optically transparent substrate, and a light emitted from the light-emitting layer is output through the substrate and the amorphous oxide.

8. The light-emitting device according to claim 7, wherein the field effect transistor is arranged between the substrate and the light-emitting layer.

9. The light-emitting device according to claim 1, wherein at least one of the drain electrode of the field effect transistor and the second electrode is formed of an optically transparent electroconductive oxide.

10. The light-emitting device according to claim 1, wherein the light-emitting element is an electroluminescent element.

11. The light-emitting device according to claim 1, wherein a plurality of the light-emitting elements are arranged at least in a single row.

12. The light-emitting device according to claim 11, wherein the light-emitting element is arranged so as to be adjacent to the field effect transistor.

13. An electrophotographic device having

a photoreceptor,

an electrifier for electrifying the photoreceptor,

an exposing light source for exposing the photoreceptor in order to form a latent image on the photoreceptor, and

a developing unit for developing the latent image, wherein

the exposing light source has the light-emitting device according to claim 11.

14. A light-emitting device having a light-emitting element comprising first and second electrodes and a light-emitting layer existing between the first and second electrodes, and a field effect transistor for driving the light-emitting element, wherein

wherein an electron mobility of an active layer of the field effect transistor tends to increase with increasing electron carrier concentration.

15. A light-emitting device having a light-emitting element comprising first and second electrodes and a light-emitting layer existing between the first and second electrodes, and a field effect transistor for driving the light-emitting element, wherein

the active layer of the field effect transistor includes such a transparent amorphous-oxide semiconductor as to be capable of realizing a normally off state.

16. The light-emitting device according to claim 15, wherein the transparent amorphous-oxide semiconductor has an electronic carrier concentration of less than 10¹⁸/cm³, which is sufficiently few in realizing the normally off state.

17. An active matrix display device comprising a light-emitting element comprising first and second electrodes and a light-emitting layer existing between the first and second electrodes and a field effect transistor for driving the light-emitting element, and a picture element circuit arranged into a two-dimensional matrix form, wherein

the active layer of the field effect transistor includes such a transparent amorphous-oxide semiconductor as to be capable of realizing a normally off state.

18. The active matrix display device according to claim 17, wherein the transparent amorphous-oxide semiconductor has an electronic carrier concentration of less than 10¹⁸/cm³, which is sufficiently few in realizing the normally off state.

19. A display article comprising;

a light-emitting element comprising first and second electrodes and a light-emitting layer existing between the first and second electrodes and a field effect transistor for driving the light-emitting element, wherein

an active layer of the field effect transistor includes an amorphous oxide semiconductor.

20. The display article according to claim 19, wherein the amorphous oxide is any one selected from the group consisting of an oxide containing In, Zn and Sn;

an oxide containing In and Zn;

an oxide containing In and Sn; and

an oxide containing In.

21. The display article according to claim 19, wherein the transistor is a normally-off type transistor.