Method of and System for Simulating a Light-Emitting Device

• US 20080133188A1
• Filed: 10/23/2007
• Published: 06/05/2008
• Est. Priority Date: 11/30/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Nakamura, Hajime
• Granted Patent: US 7,523,028 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G06F 2111/08 Probabilistic or stochastic CAD
• CPC Class Codes: G06F 2111/10 Numerical modelling
• CPC Class Codes: G06F 2119/06 Power analysis or power optimisation
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

A system for simulating a characteristic of a light-emitting device includes a transport calculating module for calculating a concentration of carriers in the light-emitting device. The system includes an optical calculating module for calculating data sets including a total emission power factor of excitons set and a light extraction efficiency data. A diffusion calculating uses the exciton formation rate and the total emission power factor to calculate a concentration of excitons and a total deactivation rate of the excitons. A device characteristics calculating module uses the light extraction efficiency data set and a radiative deactivation rate calculated from the total deactivation rate to calculate a device characteristic of the light-emitting device.

Claims

1. A simulation system for simulating a characteristic of a light-emitting device, the simulation system comprising:

transport calculating means for calculating a concentration of carriers in the light-emitting device and for storing a carrier recombination rate as an exciton formation rate in a storage device;

optical calculating means for calculating data sets including a total emission power factor of excitons set and a light extraction efficiency data, and for storing the data sets in the storage device;

diffusion calculating means for reading the exciton formation rate and said total emission power factor, and for calculating a concentration of excitons and a total deactivation rate of the excitons; and

device characteristics calculating means for calculating a device characteristic of the light-emitting device in a measurable dimension by using said light extraction efficiency data set and a radiative deactivation rate calculated from said total deactivation rate.

2. The simulation system according to claim 1, further comprising:

a database that manages optical data defining a structure of the light-emitting device, electrical data defining a characteristic of the carriers, and exciton data defining a characteristic of the excitons;

wherein the transport calculating means, the optical calculating means, and the diffusion calculating means read the electrical data, the optical data, and the exciton data, respectively, to calculate their respective calculations.

3. The simulation system according to claim 1, wherein the diffusion calculating means includes means for calculating the concentration of excitons using quantum efficiency when the excitons undergo nonradiative deactivation.

4. The simulation system according to claim 1, wherein said optical calculating means comprises:

means for calculating a fraction of dipoles whose dipole moment lies parallel to a light-emitting surface of the light-emitting device;

means for calculating a first data set providing light extraction efficiency of light emission toward the light-emitting surface; and

,

means for storing the first data set in a storage device.

5. The simulation system according to claim 4, wherein said optical calculation means further comprises:

means for summing the light extraction efficiency and a spectral emission intensity of excitons over a wavelength range, thereby calculating a second data set including said total emission power factor; and

,

means for storing the second data set in the storage device.

6. The simulation system according to claim 5, wherein said optical calculation means further comprises:

photometric quantity calculating means for calculating a third data set including a set of color-space coordinates defined in a color space using the first data set and color space data; and

,

means for storing the third data set in the storage device.

7. The simulation system according to claim 6, further comprising:

multilayer-characteristics calculating means for calculating a fourth data set including data pertaining to reflection in a multilayer structure using a Fresnel coefficient; and

,

means for storing the fourth data set in the storage device.

8. The simulation system according to claim 6, further comprising:

means for summing the third data set over a wavelength range, thereby calculating a light-emitting characteristic at a position coordinate in the light-emitting device from the third data set.

9. A method of simulating a characteristic of a light-emitting device, which comprises:

calculating a concentration of carriers in a light-emitting device;

calculating a carrier recombination rate from said concentration of carriers;

calculating a total emission power factor of excitons;

calculating a light extraction efficiency;

calculating a concentration of excitons from said carrier recombination rate and said total emission power factor;

calculating a radiative deactivation rate from said concentration of excitons; and

calculating a device characteristic of the light-emitting device using said light extraction efficiency and said radiative deactivation rate.

10. The method as claimed in claim 9, further comprising:

storing said carrier recombination rate as an exciton formation rate in a storage device; and

,

said concentration of excitons is calculated from said exciton formation rate and said total emission power factor.

11. The method as claimed in claim 10, wherein said calculating said concentration of excitons includes:

storing said total emission power factor in a storage device;

reading said total emission power factor; and

,

numerically solving coupled differential equations including the exciton formation rate, and thus calculating the concentration of excitons.

12. The method as claimed in claim 11, wherein said calculating said radiative deactivation rate includes:

storing said concentration of excitons in association with a position coordinate in said light-emitting device as array data in said storage device.

13. The method as claimed in claim 9, wherein:

said concentration of carriers is calculated from electrical data; and

,

said total emission power factor and said light extraction efficiency are calculated from optical data.

14. The method as claimed in claim 9, wherein said calculating said concentration of excitons includes:

calculating said concentration of excitons using quantum efficiency when said excitons undergo nonradiative deactivation.

15. The method as claimed in claim 9, wherein said calculating said light extraction efficiency includes:

calculating, from optical data pertaining to said light-emitting device, a fraction of dipoles whose dipole moment lies parallel to a light-emitting surface of the light-emitting device; and

,

calculating a ratio of light emitted to the light-emitting surface.

16. The method as claimed in claim 15, wherein said calculating said total emission power factor includes:

summing said light extraction efficiency and a spectral emission intensity of excitons over a wavelength range.

17. The method as claimed in claim 16, further comprising:

calculating a set of color-space coordinates defined in a color space using color space data.