Light-emitting device

• US 7,872,259 B2
• Filed: 11/09/2005
• Issued: 01/18/2011
• 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
• Primary Examiner(s): Fahmy; Wael M
• Assistant Examiner(s): Yang; Minchul
• Application Number:
  US11/269,768
• Publication Number:
  US 20060113549A1
• Time in Patent Office: 1,896 Days
• Field of Search: 257/79, 257/43, 257/57, 257/52, 257/55, 257/56, 257/59, 257/62, 257/72, 257/E29.083, 257/E29.092, 257/E29.101
• 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

an active layer of the field effect transistor comprises an amorphous oxide of a compound having

(a) a composition when in crystalline state represented by In₂₋

xM3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds;

(b) an electric carrier concentration of greater than 10¹²/cm³ and lesser than 10¹⁸/cm³ wherein a current between a drain terminal and a source terminal of the field effect transistor when no gate voltage is applied is less than 10 microamperes, and wherein an electron mobility of the amorphous oxide increases when the electron carrier concentration increases; and

(c) controlled oxygen defect density resulting from treatment in an atmosphere including oxygen at a predetermined pressure during or after formation of the active layer of the amorphous oxide.

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. The electrophotographic device according to claim 13, wherein the amorphous oxide contains a group-IV element M4, wherein M4 is selected from the group consisting of Sn, Si, Ge and Zr.

16. The light-emitting device according to claim 1, wherein the amorphous oxide contains a group-IV element M4, wherein M4 is selected from the group consisting of Sn, Si, Ge and Zr.

17. The light-emitting device according to claim 1 or 15, wherein the light-emitting element and the field effect transistor are layered.

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

an active layer of the field effect transistor comprises a transparent amorphous oxide semiconductor having

(a) a composition when in crystalline state represented by In₂₋

xM3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds;

(b) an electric carrier concentration of greater than 10¹²/cm³ and lesser than 10¹⁸/cm³, wherein the amorphous oxide semiconductor is capable of realizing a normally off state such that a current between a drain terminal and a source terminal of the field effect transistor when no gate voltage is applied is less than 10 microamperes, and wherein an electron mobility of the amorphous oxide semiconductor increases when the electron carrier concentration increases; and

(c) controlled oxygen defect density resulting from treatment in an atmosphere including oxygen at a predetermined pressure during or after formation of the active layer of the amorphous oxide.

18. The light-emitting device according to claim 15, wherein the amorphous oxide contains a group-IV element M4, wherein M4 is selected from the group consisting of Sn, Si, Ge and Zr.

19. 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

an active layer of the field effect transistor includes such a transparent amorphous oxide semiconductor having

(a) a composition when in crystalline state represented by In₂₋

xM3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds;

(b) an electric carrier concentration of greater than 10¹²/cm³ and lesser than 10¹⁸/cm³, wherein the amorphous oxide semiconductor is capable of realizing a normally off state such that a current between a drain terminal and a source terminal of the field effect transistor when no gate voltage is applied is less than 10 microamperes, and wherein an electron mobility of the amorphous oxide semiconductor increases when the electron carrier concentration increases; and

(c) controlled oxygen defect density resulting from treatment in an atmosphere including oxygen at a predetermined pressure during or after formation of the active layer of the amorphous oxide.

20. The active matrix display device according to claim 19, wherein the light-emitting element and the field effect transistor are layered.

21. The active matrix display device according to claim 19, wherein the amorphous oxide contains a group-IV element M4, wherein M4 is selected from the group consisting of Sn, Si, Ge and Zr.

22. 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 having

(a) a composition when in crystalline state represented by In<sub>2−

x</sub>M3_xO₃(Zn<sub>1−

y</sub>M2_yO)_m, wherein M2 is Mg or Ca;

M3 is B, Al, Ga or Y;

0≦

x≦

2;

0≦

y≦

1; and

m is zero or a natural number less than 6, or a mixture of said compounds;

(b) an electric carrier concentration of greater than 10¹²/cm³ and lesser than 10¹⁸/cm³, wherein a current between a drain terminal and a source terminal of the field effect transistor when no gate voltage is applied is less than 10 microamperes, and wherein an electron mobility of the amorphous oxide semiconductor increases when the electron carrier concentration increases; and

(c) controlled oxygen defect density resulting from treatment in an atmosphere including oxygen at a predetermined pressure during or after formation of the active layer of the amorphous oxide.

23. The display article according to claim 22, 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.

24. The display article according to claim 22, wherein the transistor is a normally-off type transistor.

25. The display article according to claim 22, wherein the light-emitting element and the field effect transistor are layered.

26. The display article according to claim 22, wherein the amorphous oxide contains a group-IV element M4, wherein M4 is selected from the group consisting of Sn, Si, Ge and Zr.