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Method for measuring GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra

A technology of photoluminescence spectroscopy and polarized electric field, applied in the direction of electrostatic field measurement, etc., can solve the problem of low accuracy, achieve the effect of convenient sample preparation, simple sample requirements, and meet urgent needs

Active Publication Date: 2014-01-22
INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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Problems solved by technology

[0005] The technical problem to be solved by the present invention is that the accuracy of the existing LED polarization electric field measurement method is not high, and it is difficult to provide support for the efficiency research of LEDs

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  • Method for measuring GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra
  • Method for measuring GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra
  • Method for measuring GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra

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Embodiment Construction

[0021] From the perspective of electric field balance, the present invention counteracts the effect of its built-in polarization electric field by applying an electric field formed by reverse bias to GaN-based LEDs. According to the energy band bending theory, combined with the wavelength change of GaN-based LEDs, the internal polarity of LEDs is measured. create a polarizing electric field.

[0022] In practical applications, LEDs can be either LED epitaxial wafers or LED chips. LED epitaxial wafers usually refer to LED full-structure wafers (Wafer), and through etching, thinning, evaporation, scribing, packaging and other processes After processing, LED chips are obtained. The structure of GaN-based LED epitaxial wafer is as follows: figure 1 As shown, it is the substrate, the low-temperature nucleation layer, the low-temperature buffer layer, the n-type layer, the active region and the p-type layer in sequence from bottom to top, and the active region is a double heterojun...

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Abstract

The invention discloses a method for measuring a GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra. The method comprises the following steps of manufacturing a GaN-based LED testing sample, completely radiating the testing sample by utilizing laser, and measuring output light current and light voltage; connecting a positive voltage with an n electrode of the testing sample and connecting a negative voltage with a p electrode of the testing sample to form reverse bias; applying the reverse bias equal to the light voltage to the testing sample; measuring the photoluminescence spectra of the testing sample, and recording light-emitting wavelength of the testing sample; increasing the reverse bias step by step, and measuring the spectrum and the wavelength; when the wavelength is gradually changed from the short wavelength to the long wavelength, stopping increasing the reverse bias and stopping measuring; reducing the light voltage from the reverse bias when the measurement is stopped to obtain polarization voltage of the testing sample; calculating a polarization electric field of the testing sample according to the polarization voltage. According to the method for measuring the GaN-based LED polarization electric field by utilizing the photoluminescence spectra, which is disclosed by the invention, the requirements on samples are simple, the sample manufacturing is convenient, the testing result can be quickly obtained, and the active demands on test data in production, research and development techniques are facilitated to be met.

Description

technical field [0001] The invention relates to the technical field of semiconductor LED testing, in particular to a method for measuring the polarization electric field of GaN-based LEDs by using photoluminescence spectroscopy. Measurement of the electric field. Background technique [0002] With the rapid development of GaN-based white LEDs, the efficiency of LEDs has been greatly improved, and they have gradually replaced the incandescent and fluorescent lamps currently used for lighting. However, compared with the theoretical value, its efficiency still has a lot of room for improvement, especially under high current, the efficiency droop phenomenon of LED is very serious. Regarding the droop effect, a large factor lies in the polar growth of GaN brought about by the polar substrate material, thereby forming a large built-in polarization electric field (piezoelectric polarization electric field) inside the LED, and under large current injection, The energy band bending...

Claims

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Application Information

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IPC IPC(8): G01R29/12
Inventor 魏学成赵丽霞张连于治国王军喜曾一平李晋闽
Owner INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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