基于耦合量子阱的GaN基垂直結(jié)構(gòu)LED器件研究
發(fā)布時間：2019-04-25 14:12
【摘要】：與Ga N基正裝結(jié)構(gòu)發(fā)光二極管(Light Emitting Diode,LEDs)芯片相比,Ga N基垂直結(jié)構(gòu)LED芯片解決了電流密度過大及導(dǎo)致散熱不佳等問題,更適合應(yīng)用于大電流注入的大功率LED照明。而在大電流注入時Ga N基LED會出現(xiàn)效率下降問題。因此,研究解決效率下降問題對提高Ga N基垂直結(jié)構(gòu)LED的效率具有重要的實際意義。針對傳統(tǒng)In Ga N/Ga N多量子阱結(jié)構(gòu)中載流子分布不均勻的問題,通過APSYS仿真軟件,建立了七組耦合量子阱數(shù)量不等的Ga N基垂直結(jié)構(gòu)LED芯片二維模型,仿真結(jié)果表明,耦合量子阱的引入提高了空穴在In Ga N/Ga N多量子阱中的分布均勻性及空穴與電子的輻射復(fù)合率。仿真結(jié)果還表明,當耦合量子阱數(shù)量小于或等于5對時,Ga N基垂直結(jié)構(gòu)LED芯片模型的有效輻射復(fù)合率、正向偏壓、光輸出功率均隨著耦合量子阱數(shù)量的增加而大幅度改善。當耦合量子阱數(shù)量大于5對時,Ga N基垂直結(jié)構(gòu)LED芯片模型的各方向特性與5對耦合量子阱模型相比均無明顯提升。其中具有5對耦合量子阱的Ga N基垂直結(jié)構(gòu)LED芯片模型,與只有傳統(tǒng)量子阱的模型相比,在注入電流為350 m A時其正向偏壓下降了0.46 V,光輸出功率提高了39.4%。在仿真結(jié)果的基礎(chǔ)上,利用MOCVD技術(shù)、激光剝離、電鍍金屬基板等技術(shù)制備了具有5對耦合量子阱的Ga N基垂直結(jié)構(gòu)LED芯片樣品,與只有傳統(tǒng)量子阱的Ga N基垂直結(jié)構(gòu)LED芯片相比,在注入電流為350 m A時,其正向偏壓下降了0.68 V,光輸出功率提升了53.0%,有更好的電流響應(yīng)效率;其外量子效率下降到最大值的67.5%,而只有傳統(tǒng)量子阱的樣品下降到了37.7%,有效地緩解了大電流注入下Ga N基LEDs效率下降的問題。并通過討論樣品EL譜的變化情況,分析了耦合量子阱Ga N基LEDs在大電流下效率下降得到緩解的原因。該課題的研究結(jié)果為實現(xiàn)大功率LED芯片應(yīng)用于通用照明領(lǐng)域起到了至關(guān)重要的作用。
[Abstract]:Compared with Ga N-based forward-mounted light emitting diode (Light Emitting Diode,LEDs) chip, Ga N-based vertical structure LED chip solves the problems of high current density and poor heat dissipation, and is more suitable for high-power LED lighting with high current injection. However, in the case of high current injection, the efficiency of Ga N-based LED will decrease. Therefore, it is of great practical significance to study and solve the problem of decreasing efficiency for improving the efficiency of Ga N-based vertical LED. In order to solve the problem of uneven carrier distribution in traditional In Ga N/Ga-N multi-quantum well structures, seven sets of two-dimensional models of Ga-N-based vertical structure LED chips with different number of coupled quantum wells are established by APSYS simulation software. The simulation results show that: 1. The introduction of coupled quantum wells improves the uniformity of hole distribution in In Ga N/Ga-N multiple quantum wells and the radiative recombination rate of holes and electrons. The simulation results also show that when the number of coupled quantum wells is less than or equal to 5 pairs, the effective radiation recombination rate, forward bias and optical output power of the, Ga N-based vertical structure LED chip model are greatly improved with the increase of the number of coupled quantum wells. When the number of coupled quantum wells is more than 5 pairs, the, Ga N-based vertical structure LED chip model has no significant improvement compared with the 5-pair coupled quantum well model. The Ga N-based vertical structure LED chip model with 5 pairs of coupled quantum wells is compared with the conventional quantum well model. Compared with the conventional quantum well model, the forward bias decreases by 0.46V and the optical output power increases by 39.4% when the injection current is 350mA. Based on the simulation results, the Ga N-based vertical structure LED chip samples with 5 pairs of coupled quantum wells were fabricated by using MOCVD technology, laser stripping, plating metal substrate and so on. When the injection current is 350mA, the forward bias decreases by 0.68V and the optical output power increases by 53.0%, compared with the Ga N-based vertical structure LED chip with only traditional quantum well, which has better current response efficiency. The external quantum efficiency decreased to 67.5% of the maximum, while only the conventional quantum well samples decreased to 37.7%, which effectively alleviated the decrease of Ga N-based LEDs efficiency under high current injection. By discussing the variation of the EL spectra of the samples, the reasons for the decrease of the efficiency of the coupled quantum well Ga N-based LEDs under large current are analyzed. The research results of this paper play an important role in the application of high power LED chip in general lighting field.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN312.8
本文編號：2465191
[Abstract]:Compared with Ga N-based forward-mounted light emitting diode (Light Emitting Diode,LEDs) chip, Ga N-based vertical structure LED chip solves the problems of high current density and poor heat dissipation, and is more suitable for high-power LED lighting with high current injection. However, in the case of high current injection, the efficiency of Ga N-based LED will decrease. Therefore, it is of great practical significance to study and solve the problem of decreasing efficiency for improving the efficiency of Ga N-based vertical LED. In order to solve the problem of uneven carrier distribution in traditional In Ga N/Ga-N multi-quantum well structures, seven sets of two-dimensional models of Ga-N-based vertical structure LED chips with different number of coupled quantum wells are established by APSYS simulation software. The simulation results show that: 1. The introduction of coupled quantum wells improves the uniformity of hole distribution in In Ga N/Ga-N multiple quantum wells and the radiative recombination rate of holes and electrons. The simulation results also show that when the number of coupled quantum wells is less than or equal to 5 pairs, the effective radiation recombination rate, forward bias and optical output power of the, Ga N-based vertical structure LED chip model are greatly improved with the increase of the number of coupled quantum wells. When the number of coupled quantum wells is more than 5 pairs, the, Ga N-based vertical structure LED chip model has no significant improvement compared with the 5-pair coupled quantum well model. The Ga N-based vertical structure LED chip model with 5 pairs of coupled quantum wells is compared with the conventional quantum well model. Compared with the conventional quantum well model, the forward bias decreases by 0.46V and the optical output power increases by 39.4% when the injection current is 350mA. Based on the simulation results, the Ga N-based vertical structure LED chip samples with 5 pairs of coupled quantum wells were fabricated by using MOCVD technology, laser stripping, plating metal substrate and so on. When the injection current is 350mA, the forward bias decreases by 0.68V and the optical output power increases by 53.0%, compared with the Ga N-based vertical structure LED chip with only traditional quantum well, which has better current response efficiency. The external quantum efficiency decreased to 67.5% of the maximum, while only the conventional quantum well samples decreased to 37.7%, which effectively alleviated the decrease of Ga N-based LEDs efficiency under high current injection. By discussing the variation of the EL spectra of the samples, the reasons for the decrease of the efficiency of the coupled quantum well Ga N-based LEDs under large current are analyzed. The research results of this paper play an important role in the application of high power LED chip in general lighting field.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN312.8
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