Method for electrical doping a semiconductor material with Cesium

• US 7,507,649 B2
• Filed: 09/30/2005
• Issued: 03/24/2009
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: Novaled AG
• Inventors: Romainczyk, Tilmann, Werner, Ansgar
• Primary Examiner(s): Picardat; Kevin M
• Application Number:
  US11/241,477
• Publication Number:
  US 20060079004A1
• Time in Patent Office: 1,271 Days
• Field of Search: 438/1, 438/99, 438/70, 438/510, 438/517, 438/542, 438/565, 438/567, 438/568
• US Class Current: 438/567
• CPC Class Codes: H10K 50/165 comprising dopants

Abstract

The invention relates to a method for doping a semiconductor material with Cesium, wherein said semiconductor material is exposed to a cesium vapor. Said Cesium vapor is provided by Cesium sublimation from a Cesium alloy. There is also provided an organic light emitting diode comprising at least one layer of a Cesium doped organic semiconductor material, wherein said at least one layer of said Cesium doped organic semiconductor material is doped with Cesium provided by Cesium evaporation of Cesium from a Cesium alloy. The Cesium vapor is preferably provided by Cesium sublimation from a standard organic material deposition evaporator.

Claims

1. A method for electrical doping a semiconductor material with Cesium, wherein said semiconductor material is exposed to a Cesium vapor, characterized in that said Cesium vapor is provided by Cesium sublimation from a Cesium alloy.

2. The method as claimed in claim 1, wherein said Cesium vapor is provided by Cesium sublimation from a Gallium Cesium alloy.

3. The method as claimed in claim 2, wherein said Cesium vapor is provided by Cesium sublimation from a Ga₇Cs₁₁ alloy.

4. The method as claimed in claim 1, wherein said semiconductor material is provided as a thin film material.

5. The method as claimed in claim 1, wherein said Cesium sublimation is performed in an evaporator at a sublimation temperature of about 420°

C. or less.

6. The method as claimed in claim 5, wherein said Cesium sublimation is monitored by a quartz microbalance.

7. The method as claimed in claim 6, wherein said quartz microbalance is cooled by water.

8. The method as claimed in claim 1, wherein said Cesium alloy is provided as a solid material, and said solid material is preheated for generating a protective shell.

9. The method as claimed in claim 1, wherein said semiconductor material is an organic material.

10. The method as claimed in claim 1, wherein said semiconductor material is an organic electron transport material.

11. The method as claimed in claim 1, wherein said Cesium vapor is provided by Cesium sublimation from a standard organic material deposition evaporator.

12. The method as claimed in claim 11, wherein said standard organic material deposition evaporator is a Knudsen type crucible.

13. The method as claimed in claim 11, wherein said standard organic material deposition evaporator is linear source type.

14. The method as claimed in claim 11, wherein said standard organic material deposition evaporator is an evaporator with a linear head connected to a crucible volume by a tube system.

15. The method as claimed in claim 14, wherein a temperature of said tube system of said standard organic material deposition evaporator is controlled to be below a temperature in said crucible volume.

16. The method as claimed in claim 1, wherein said Cesium sublimation is performed in an evaporator at a sublimation temperature of about 300°

C. or less.