Method for measuring LED internal quantum efficiency

Abstract

The invention discloses a method for measuring LED internal quantum efficiency by using variable laser excitation density and fluorescence spectra. The method comprises the following steps that: a test sample is made, wherein the test sample has a quantum well structure and at least comprises a substrate, a low-temperature nucleation layer, a low-temperature buffer layer, an n-type layer, an active region and a p-type layer which are sequentially arranged from bottom to up; the LED sample is put into a sample chamber of a spectrograph, and a round attenuation sheet is arranged on an optical path from a laser to the sample, and laser power is continuously adjustable through adjusting the position of the attenuation sheet; a light splitting optical path is arranged, and the light splitting ratio of the light splitting optical path is constant, and the laser power of the test optical path can be obtained through the real-time measurement of the light splitting optical path, and laser excitation densities can be obtained through measuring the size of light spots of the test optical path; different laser power is measured through changing the position of the round laser attenuation sheet, such that corresponding laser excitation densities can be calculated, and then, corresponding fluorescence spectra can be obtained through a detector; the laser excitation densities and corresponding fluorescence spectrum integral strength are calculated and listed; and internal quantum efficiency can be obtained through fitting according to the rate equation and the internal quantum efficiency definition.

Description

technical field [0001] The invention relates to the technical field of semiconductor LED testing, in particular to a method for measuring the internal quantum efficiency of LEDs, which is applicable to the measurement of the internal quantum efficiencies of all LEDs such as blue light, green light, purple light and ultraviolet light. Background technique [0002] Currently, the external quantum efficiency of LEDs can be directly obtained through electrical measurements. To measure the internal quantum efficiency of LEDs, there is currently no suitable direct measurement method. At present, the general internal quantum efficiency test method uses the intensity ratio of the low-temperature fluorescence spectrum and the room temperature fluorescence spectrum to characterize the internal quantum efficiency of the LED. Change, and the most important problem of this kind is that it needs a low temperature environment, which brings great inconvenience to daily detection. Content...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is that the existing LED internal quantum efficiency measurement method has the disadvantages of high environmental requirements, inconvenient operation and low test accuracy.

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