CN103529310A - Method for measuring GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra - Google Patents
Method for measuring GaN-based LED (light emitting diode) polarization electric field by utilizing photoluminescence spectra Download PDFInfo
- Publication number
- CN103529310A CN103529310A CN201310459347.8A CN201310459347A CN103529310A CN 103529310 A CN103529310 A CN 103529310A CN 201310459347 A CN201310459347 A CN 201310459347A CN 103529310 A CN103529310 A CN 103529310A
- Authority
- CN
- China
- Prior art keywords
- electric field
- specimen
- measuring
- voltage
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Testing Of Individual Semiconductor Devices (AREA)
- Led Devices (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
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
The present invention relates to semiconductor LED technical field of measurement and test, be specifically related to a kind of method of utilizing the polarized electric field of photoluminescence spectrometry GaN base LED, the present invention is applicable to the measurement of the polarized electric field of all GaN base LED such as blue light, green glow, purple light and ultraviolet light.
Background technology
Along with the fast development of GaN base white light LEDs, LED efficiency has had large increase, progressively replaces at present illumination incandescent lamp and fluorescent light used at present.But its efficiency relative theory value also has very large room for promotion, particularly, under large electric current, the efficiency droop phenomenon of LED is very serious.About droop effect, very large factor is the GaN polar growth that polarity backing material brings, thereby in LED inside, has formed large built-in polarized electric field (piezoelectric polarization electric field), and under large electric current injects, further increase again band curvature, thereby strengthened the polarization effect of LED.For this reason, much adopt the method for the growing nonpolar GaN materials such as nonpolar substrate to arise at the historic moment, but also do not have at present the report of high-level efficiency LED to occur, and still there is polarization effect in its inside, the luminescence efficiency of LED is still had to larger impact.
In order to measure the polarized electric field of LED, used for reference the method for a lot of GaAs systems, as wavelength shift and component change calculations method, but because GaN has higher dislocation desity, its emission wavelength and component not exclusively corresponding, be difficult to Measurement accuracy.Therefore study the Accurate measurement of polarized electric field, the improved efficiency research of LED is had great importance.
Summary of the invention
(1) technical matters that will solve
Technical matters to be solved by this invention is that the accuracy of existing LED polarized electric field measuring method is not high, is difficult to provide support for the efficient studies of LED.
(2) technical scheme
The invention provides a kind of method of utilizing photoluminescence spectrometry GaN base LED polarized electric field, comprise step S1: make GaN base LED specimen, in vain lower supreme substrate, low temperature nucleating layer, low temperature buffer layer, N-shaped layer, active area and the p-type layer of being followed successively by of described specimen, has respectively p electrode and n electrode on p-type layer and N-shaped layer; Step S2: utilize described in the complete irradiation of laser specimen and measure photocurrent and the photovoltage of its output; Step S3: the n electrode to described specimen connects positive voltage, and p electrode connects negative voltage, forms reverse biased; Step S4: described specimen is applied to the reverse biased that equals photovoltage, measure its photoluminescence spectrum, and record its emission wavelength, then substep increases reverse biased, and measure its spectrum and wavelength, and at wavelength, by shortening gradually, transfer to when elongated, stop increasing reverse biased and stop measuring; Step S5: the reverse biased while utilizing step S4 to stop measuring deducts the polarizing voltage that photovoltage that step S2 obtains obtains described specimen, calculates the polarized electric field of specimen according to this polarizing voltage.
According to the preferred embodiment of the present invention, in step S1, the step of utilizing GaN base LED epitaxial wafer to make specimen is: on described epitaxial wafer, choose a test zone, a side to test zone is carried out etching, etching depth arrives the surface of N-shaped layer, form a table top, and prepare n electrode on this table top; At the opposite side of test zone, prepare p electrode, make specimen.
According to the preferred embodiment of the present invention, in described step S2, adopt resonance laser instrument to produce described laser.
According to the preferred embodiment of the present invention, described step S3 carries out in the temperature environment of 10K～450K.
According to the preferred embodiment of the present invention, in step S4, the step-length of substep is 1V.
According to the preferred embodiment of the present invention, in step S5, according to following formula, calculate the polarized electric field of specimen: E=(U
1-U
0)/d, wherein, the electric field intensity that E is described polarized electric field, U
1reverse biased while stopping measuring for described step S4, U
0for the photovoltage that described step S2 obtains, the active area thickness that d is described specimen.
(3) beneficial effect
The present invention utilizes band curvature theoretical, by applying reverse biased, enables band and from inclination, becomes level and tilt, by the reverse biased of balance, as polarizing voltage, and then calculates polarized electric field, symbolizes intuitively the polarized electric field that LED internal polarization effect causes.
Due to the fluctuation of In component in the lattice mismatch of InGaN and GaN and InGaN, cause the white hair polarization of LED inside and answer polarization to be difficult to direct measurement.The present invention changes by directly measure photoluminescence wavelength under reverse biased, can calculate accurately the polarized electric field of LED inside.
The present invention is simple to sample requirement, and sample preparation is convenient, can obtain quickly test result, is conducive to meet produce and research and develop the active demand to test data in technique.
Accompanying drawing explanation
Fig. 1 is the structural representation of GaN base LED epitaxial wafer;
Fig. 2 is the structural representation of GaN base LED specimen of the present invention;
Fig. 3 is the structural representation of proving installation of the present invention;
Fig. 4 can be with schematic diagram when specimen is applied to reverse biased.
Embodiment
The present invention, from electric field balance angle, offsets the effect of its built-in polarized electric field by GaN base LED being applied to the electric field of reverse biased formation, theoretical according to band curvature, measures the built-in polarized electric field of LED in conjunction with the wavelength variations of GaN base LED.
In practical application, LED can be both LED epitaxial wafer, can be also LED chip, and LED epitaxial wafer is commonly referred to as the full structured wafer of LED (Wafer), and by etching, attenuate, evaporation, draw and split, obtain LED chip after the processes such as encapsulation.As shown in Figure 1, it is lower supreme substrate, low temperature nucleating layer, low temperature buffer layer, N-shaped layer, active area and the p-type layer of being followed successively by vain for the structure of GaN base LED epitaxial wafer, and wherein active area is double-heterostructure, single quantum or multi-quantum pit structure.
Method of testing of the present invention comprises the steps:
Step S1: make GaN base LED specimen, in vain lower supreme substrate, low temperature nucleating layer, low temperature buffer layer, N-shaped layer, active area and the p-type layer of being followed successively by of described specimen, has respectively p electrode and n electrode on p-type layer and N-shaped layer.
For LED chip, while making specimen, only need to remove the encapsulating material of chip surface, make the laser can direct projection sample.
For LED epitaxial wafer, can first on epitaxial wafer, choose a test zone, a side of test zone is carried out to etching, etching depth arrives the surface of N-shaped layer, forms a table top, and prepare n electrode on this table top; At the opposite side of test zone, prepare p electrode, make specimen 2.The structure of the specimen of making as shown in Figure 2.
Step S2: utilize described in the complete irradiation of laser specimen and measure photocurrent and the photovoltage of its output.Laser instrument is preferably corresponding resonance laser instrument.
Step S3: the n electrode to described specimen connects positive voltage, and p electrode connects negative voltage, forms reverse biased.
This is executed biased step and can realize by a direct supply.This step can be carried out when 10K～450K, is preferably specimen is placed in to low temperature environment, is conducive to like this confirmation of spectral wavelength and reads.Preferred low temperature environment is 10K.Under low temperature environment, need in addition to consider that resistance in series increases the factors such as voltage rising of introducing.If do not possess low temperature environment, the present invention at room temperature also can carry out.
Step S4: described specimen is applied to the reverse biased that equals photovoltage, measure its photoluminescence spectrum, and record its emission wavelength, after then substep increases reverse biased, measure its spectrum and wavelength, when wavelength is when blue shift transfers red shift to gradually, stop increasing reverse biased and stop measuring.
As shown in Figure 4, by the step-length of 1V, measure respectively the fluorescence spectrum under different bias voltages, its wavelength is along with the increase of reverse biased, blue shift gradually, reverse biased now makes the band gap of LED become large, can be with from inclination, become parallel; Can be with parallel after, along with the further increase of reverse biased, can be with to tilting in the other direction, band gap diminishes, now wavelength starts red shift.
Step S5: the reverse biased while utilizing step S4 to stop measuring deducts the polarizing voltage that photovoltage that step S2 obtains obtains described specimen, calculates the polarized electric field of this specimen according to this polarizing voltage.
According to flat rubber belting condition, E=U/d, E is electric field intensity, and U is voltage between flat rubber belting, and d is active area thickness.
Reverse biased U when step S4 stops measuring
1deducting photovoltage is exactly the polarizing voltage U of LED sample
0, be voltage U between flat rubber belting.By above-mentioned formula, calculate, draw its polarized electric field E=U/d=(U
1-U
0)/d.
For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in further detail.
This embodiment is the polarized electric field of a blue-ray LED of test, specifically comprises the steps:
Step S1: utilize metal-organic chemical vapor deposition equipment (MOCVD) or molecular beam epitaxy (MBE) growing GaN base LED epitaxial wafer, epitaxial wafer is blue light GaN base LED epitaxial wafer.As previously mentioned, its structure is followed successively by substrate, low temperature nucleating layer, low temperature buffer layer, N-shaped layer, active area and p-type layer, and wherein active area is multi-quantum pit structure, and the number of Multiple Quantum Well is 9, and the thickness of trap is 3nm, and barrier layer thickness is 12nm.
On epitaxial wafer, choose a test zone, a superincumbent side adopts ICP to carry out etching, and etching depth arrives the following 1 μ m left and right, surface of N-shaped layer, form a table top, and utilize PECVD to prepare n electrode thereon, at opposite side, prepare p electrode, and add lead-in wire, make specimen.This step also can adopt LED chip technique to make standard LED chip;
Step S2: specimen is connected to upper conductor, and be arranged on testing tool, instrumentation diagram as shown in Figure 3, is utilized the resonance complete irradiation sample of laser and measures corresponding photogenerated current and photovoltage with current voltmeter.
As shown in Figure 3, described testing tool comprises voltage source, monochromator, detector, laser instrument and temperature-controlling system etc.By voltage source, be connected with specimen, sample is applied to reverse biased; By laser instrument, to specimen irradiation, produce fluorescence; By monochromator and detector, realize collection and the spectrum test of fluorescence, and recording wavelength; Temperature-controlling system can be realized the condition of different temperatures of test request.
Step S3: by a direct voltage source, specimen n electrode is connect to positive pole, p electrode connects negative pole, forms reverse biased; And realizing path, do not add in the situation of external bias voltage and regulate spectral signal to reach maximum.For measure spectrum better, this embodiment is placed in 10K temperature by specimen.
Step S4: apply the reverse biased that equals photovoltage, measure its photoluminescence spectrum, and record its emission wavelength, then the step-length with 1V increases reverse biased, and measure its spectrum and wavelength, at wavelength, by shortening gradually, transfer to and reduce step-length when elongated and measure, until find final equilibrium point.
Step S5: reverse biased now deducts the polarizing voltage that photovoltage is exactly LED sample, calculates by above-mentioned theory, draws its built-in polarized electric field.
Fig. 4 can be with schematic diagram when specimen is applied to reverse biased, and wherein (a) figure is polarized electric field original state, (b) figure be with reverse biased balance after state, (c) figure is the excessive rear state of reverse biased.Due to the lattice mismatch of InGaN and GaN, at the inner piezoelectric polarization that produces of quantum well, cause being with inclination, as shown in (a), band gap diminishes, and along with specimen is applied after reverse biased, has suppressed polarization effect, increase along with reverse biased, reverse biased and polarizing voltage are offset, now can be with become parallel, as shown in (b), and the continuation increase of reverse biased can enable band to tilting in the other direction, as shown in (c).
In the present invention, Measurement accuracy balance reverse biased is the key of Measurement accuracy LED polarized electric field, by Measurement accuracy photovoltage and reverse biased, and reverse biased is deducted to photovoltage as balance polarizing voltage, has improved test accuracy.
Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (6)
1. a method of measuring GaN base LED polarized electric field, comprises the steps:
Step S1: make GaN base LED specimen, in vain lower supreme substrate, low temperature nucleating layer, low temperature buffer layer, N-shaped layer, active area and the p-type layer of being followed successively by of described specimen, has respectively p electrode and n electrode on p-type layer and N-shaped layer;
Step S2: utilize described in the complete irradiation of laser specimen and measure photocurrent and the photovoltage of its output;
Step S3: the n electrode to described specimen connects positive voltage, and p electrode connects negative voltage, forms reverse biased;
Step S4: described specimen is applied to the reverse biased that equals photovoltage, measure its photoluminescence spectrum, and record its emission wavelength, then substep increases reverse biased, and measure its spectrum and wavelength, and at wavelength, by shortening gradually, transfer to when elongated, stop increasing reverse biased and stop measuring;
Step S5: the reverse biased while utilizing step S4 to stop measuring deducts the polarizing voltage that photovoltage that step S2 obtains obtains described specimen, calculates the polarized electric field of specimen according to this polarizing voltage.
2. the method for measurement according to claim 1 GaN base LED polarized electric field, is characterized in that: in step S1, the step of utilizing GaN base LED epitaxial wafer to make specimen is:
On described epitaxial wafer, choose a test zone, a side of test zone is carried out to etching, etching depth arrives the surface of N-shaped layer, forms a table top, and prepare n electrode on this table top;
At the opposite side of test zone, prepare p electrode, make specimen.
3. the method for utilizing photoluminescence spectrometry GaN base LED polarized electric field according to claim 1, is characterized in that, adopts resonance laser instrument to produce described laser in described step S2.
4. the method for utilizing photoluminescence spectrometry GaN base LED polarized electric field according to claim 1, is characterized in that, described step S3 carries out in the temperature environment of 10K～450K.
5. the method for utilizing photoluminescence spectrometry GaN base LED polarized electric field according to claim 1, is characterized in that, in step S4, the step-length of substep is 1V.
6. the method for utilizing photoluminescence spectrometry GaN base LED polarized electric field according to claim 1, is characterized in that, in step S5, calculates the polarized electric field of specimen according to following formula:
E=(U
1-U
0)／d，
Wherein, the electric field intensity that E is described polarized electric field, U
1reverse biased while stopping measuring for described step S4, U
0for the photovoltage that described step S2 obtains, the active area thickness that d is described specimen.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310459347.8A CN103529310B (en) | 2013-09-25 | 2013-09-25 | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310459347.8A CN103529310B (en) | 2013-09-25 | 2013-09-25 | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103529310A true CN103529310A (en) | 2014-01-22 |
| CN103529310B CN103529310B (en) | 2015-12-23 |
Family
ID=49931478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310459347.8A Active CN103529310B (en) | 2013-09-25 | 2013-09-25 | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103529310B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105606982A (en) * | 2015-09-11 | 2016-05-25 | 厦门市三安光电科技有限公司 | In-situ test system of nitride light emitting diode magnetoelectricity stress coupling |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0423482A (en) * | 1990-05-18 | 1992-01-27 | Fujitsu Ltd | Method for appreciation of refractive index difference |
| JPH0666840A (en) * | 1992-08-21 | 1994-03-11 | Hamamatsu Photonics Kk | Electric field measuring device |
| US5572016A (en) * | 1995-04-25 | 1996-11-05 | Martin Marietta Corporation | Photoluminescence built-in-test for optically initiated systems |
| CN1776442A (en) * | 2005-11-23 | 2006-05-24 | 中国科学院上海技术物理研究所 | Method for detecting gallium nitride base LED quality good or not |
| CN1797795A (en) * | 2004-12-27 | 2006-07-05 | 北京大学 | Method for preparing LED chip with 2D natural scattered faces for outputting light |
| CN1801498A (en) * | 2005-01-07 | 2006-07-12 | 北京大学 | Method for preparing LED chip with separate crystal grain vertical structure |
| CN1881626A (en) * | 2005-06-14 | 2006-12-20 | 中国科学院半导体研究所 | Method for making GaN-based blue light light-emitting diode with photon microstructure |
| CN101339970A (en) * | 2007-07-03 | 2009-01-07 | 索尼株式会社 | Gallium nitride-based semiconductor element, optical device using the same, and image display apparatus using optical device |
| CN101807640A (en) * | 2010-03-05 | 2010-08-18 | 中国科学院半导体研究所 | Method for improving LED luminous efficiency by using three-dimensional polarized induction positive hole gas |
| CN102549781A (en) * | 2009-09-30 | 2012-07-04 | 住友电气工业株式会社 | Method for producing semiconductor light-emitting element |
| CN102709418A (en) * | 2012-07-16 | 2012-10-03 | 广东工业大学 | Spectrum adjustable zinc oxide (ZnO)/gallium nitride (GaN) based white light emitting device structure |
-
2013
- 2013-09-25 CN CN201310459347.8A patent/CN103529310B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0423482A (en) * | 1990-05-18 | 1992-01-27 | Fujitsu Ltd | Method for appreciation of refractive index difference |
| JPH0666840A (en) * | 1992-08-21 | 1994-03-11 | Hamamatsu Photonics Kk | Electric field measuring device |
| US5572016A (en) * | 1995-04-25 | 1996-11-05 | Martin Marietta Corporation | Photoluminescence built-in-test for optically initiated systems |
| CN1797795A (en) * | 2004-12-27 | 2006-07-05 | 北京大学 | Method for preparing LED chip with 2D natural scattered faces for outputting light |
| CN1801498A (en) * | 2005-01-07 | 2006-07-12 | 北京大学 | Method for preparing LED chip with separate crystal grain vertical structure |
| CN1881626A (en) * | 2005-06-14 | 2006-12-20 | 中国科学院半导体研究所 | Method for making GaN-based blue light light-emitting diode with photon microstructure |
| CN1776442A (en) * | 2005-11-23 | 2006-05-24 | 中国科学院上海技术物理研究所 | Method for detecting gallium nitride base LED quality good or not |
| CN101339970A (en) * | 2007-07-03 | 2009-01-07 | 索尼株式会社 | Gallium nitride-based semiconductor element, optical device using the same, and image display apparatus using optical device |
| CN102549781A (en) * | 2009-09-30 | 2012-07-04 | 住友电气工业株式会社 | Method for producing semiconductor light-emitting element |
| CN101807640A (en) * | 2010-03-05 | 2010-08-18 | 中国科学院半导体研究所 | Method for improving LED luminous efficiency by using three-dimensional polarized induction positive hole gas |
| CN102709418A (en) * | 2012-07-16 | 2012-10-03 | 广东工业大学 | Spectrum adjustable zinc oxide (ZnO)/gallium nitride (GaN) based white light emitting device structure |
Non-Patent Citations (1)
| Title |
|---|
| 陈焕庭等: "基于电容和电导特性分析GaN蓝光发光二极管老化机理", 《物理学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105606982A (en) * | 2015-09-11 | 2016-05-25 | 厦门市三安光电科技有限公司 | In-situ test system of nitride light emitting diode magnetoelectricity stress coupling |
| CN105606982B (en) * | 2015-09-11 | 2018-05-22 | 厦门市三安光电科技有限公司 | A kind of in-situ test system of iii-nitride light emitting devices magnetoelectricity stress coupling |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103529310B (en) | 2015-12-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Grillot et al. | Sixty thousand hour light output reliability of AlGaInP light emitting diodes | |
| CN110057466B (en) | Surface temperature measuring method based on LED fluorescence emission spectrum | |
| US8496353B2 (en) | Light-emitting diode (LED) module with light sensor configurations for optical feedback | |
| CN103217229A (en) | Method for measuring junction temperature of light-emitting diode and application thereof | |
| CN103528802B (en) | A kind of method utilizing electroluminescence spectrometry internal quantum efficiency of nitride | |
| Pralgauskaitė et al. | Reliability investigation of light-emitting diodes via low frequency noise characteristics | |
| CN105720480B (en) | A kind of method and its realization device of detection diffusion Zn semiconductor laser window region Zn diffusions | |
| CN102544276A (en) | Non-polar GaN thin film grown on LiGaO2 substrate, as well as manufacturing method and application thereof | |
| CN103529310B (en) | A kind of method utilizing the polarized electric field of photoluminescence spectrometry GaN base LED | |
| CN104868027A (en) | Phosphor-free GaN-based white light LED epitaxial structure and preparation method thereof | |
| US20190081208A1 (en) | Light emitting device and light emitting device package including the same | |
| KR101207660B1 (en) | AlGaAs light emitting diode having double hetero junction and method for manufacturing same | |
| Li et al. | In-situ measurement of junction temperature and light intensity of light emitting diodes with an internal sensor unit | |
| US9276166B2 (en) | Method for forming light-emitting device | |
| CN115275770A (en) | Novel LED and laser integrated structure and preparation method thereof | |
| Zhu et al. | Demonstration of GaN-based white LED grown on 4-inch patterned sapphire substrate by MOCVD | |
| CN105352620B (en) | A kind of junction temperature measurement method of light emitting diode and application | |
| Chen et al. | Efficiency and droop improvement in hybrid warm white LEDs using InGaN and AlGaInP high-voltage LEDs | |
| Raymond et al. | Photoluminescence metrology for LED characterization in high volume manufacturing | |
| Kim et al. | Effects of carrier leakage on photoluminescence properties of GaN-based light-emitting diodes at room temperature | |
| CN202454605U (en) | Nonpolar GaN film growing on LiGao2 substrate | |
| CN112098786A (en) | On-line comprehensive test system and method suitable for optical communication light-emitting device | |
| Kim et al. | MSM photodetector on a polysilicon membrane for a silicon-based wafer-level packaged LED | |
| Li et al. | 29‐3: Exploring the Temperature Dependence of GaN‐on‐GaN Homoepitaxy Micro‐LEDs | |
| KR20090053186A (en) | Method for measuring internal quantum efficiency of nitride semiconductor device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |