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Method for measuring internal quantum efficiency and light extraction efficiency of LED

A technology of internal quantum efficiency and light output efficiency, which is applied in the direction of testing optical performance, etc., can solve the problems of not being able to measure the quantum efficiency of LED chips, calibration, troubles, etc.

Active Publication Date: 2011-11-23
DONGGUAN INST OF OPTO ELECTRONICS PEKING UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

However, the variable temperature PL method is not only cumbersome, but also can only measure the epitaxial wafer of the LED, and cannot measure the internal quantum efficiency of the LED chip; and the method of optical tracing needs to set many parameters and is difficult to calibrate with the experimental data

Method used

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  • Method for measuring internal quantum efficiency and light extraction efficiency of LED
  • Method for measuring internal quantum efficiency and light extraction efficiency of LED
  • Method for measuring internal quantum efficiency and light extraction efficiency of LED

Examples

Experimental program
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Embodiment 1

[0039] Example 1: Measurement of quantum efficiency and light extraction efficiency in a high-power blue LED chip on a common sapphire substrate

[0040] 1. Using the spectroradiometer to measure the data of the LED optical power P and peak wavelength λ changing with the current I, the external quantum efficiency can be obtained by calculating the change curve of the square root of the light output efficiency Such as figure 1 The measurement range is from 0 to 400mA as indicated by the midpoint line.

[0041] 2. pass Graph to find the maximum point of external quantum efficiency and the corresponding optical power value (P 0 =4.11×4.11 (mW)).

[0042] 3. use Formula (3) pairs The curve is fitted to obtain the dimensionless parameter α=7.546 (such as figure 1 ), the fitting result residual distribution graph (such as figure 2 ).

[0043] 4. According to the fitting results, the internal quantum efficiency of the extreme point can be obtained as Then the light e...

Embodiment 2

[0045] Embodiment 2: Measurement of internal quantum efficiency and light extraction efficiency of a high-power blue LED (packaged) grown on a patterned sapphire substrate

[0046] 1. Using the spectroradiometer to measure the data of the LED optical power P and peak wavelength λ changing with the current I, the external quantum efficiency can be obtained by calculating the change curve of the square root of the light output efficiency , The measuring range is current 0 to 400mA.

[0047] 2. pass Graph to find the maximum point of external quantum efficiency and the corresponding optical power value (P 0 = 6.82 x 6.82 (mW)).

[0048] 3. use Formula (3) pairs The curve was fitted to obtain the dimensionless parameter α=8.563.

[0049] 4. According to the fitting results, the internal quantum efficiency of the extreme point can be obtained as The light extraction efficiency at the extreme point is η LEE 0 =...

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Abstract

The invention, which belongs to the field of photoelectric test technology, discloses a method for measuring an internal quantum efficiency (IQE) and a light extraction efficiency (LEE) of an LED. According to the scheme provided in the invention, an LED optical power and a relation in which a spectrum changes with a current are measured; an IQE numerical value is obtained by nonlinear regressionnearby an extremum value of an external quantum efficiency (EQE) and a corresponding LEE is calculated according to a formula; because an LEE does not change with an injection current, the LEE under different injection currents is obtained; further, corresponding LED IQEs under different injection currents are calculated and obtained by utilizing the LEE. The advantages of the method provided in the invention are as follows: routine measuring data are utilized to carry out an analysis, so that the method is simple with high operationality and a data result has high credibility; an IQE and an LEE of an LED tube core that is packaged or not packaged can be measured conveniently and the method can be used for analyzing influences of a chip structure and a packaging structure on LED efficiency; IQEs and LEEs of an LED under different currents can be measured.

Description

technical field [0001] The invention belongs to the technical field of photoelectric testing, in particular to a method for measuring the internal quantum efficiency and light extraction efficiency of LEDs. Background technique [0002] LED is a high-efficiency light-emitting device that can efficiently convert electrical energy into light energy. The luminous efficiency of LED can be characterized by the external quantum efficiency (EQE, external quantum efficiency) of LED, that is, the ratio of the number of photons emitted from LED into free space per unit time and the number of electrons injected into LED per unit time, while the external quantum efficiency of LED is given by Two parts are determined: (1) The internal quantum efficiency (IQE, internal quantum efficiency) of the LED, that is, the ratio of the number of photons emitted from the active layer of the LED per unit time to the number of electrons injected into the LED per unit time. The internal quantum effici...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01M11/02
Inventor 于彤军徐承龙颜建吴超陈志忠张国义
Owner DONGGUAN INST OF OPTO ELECTRONICS PEKING UNIV