基于耦合量子阱的GaN基垂直结构LED器件研究
发布时间：2019-04-25 14:12
【摘要】：与Ga N基正装结构发光二极管(Light Emitting Diode,LEDs)芯片相比,Ga N基垂直结构LED芯片解决了电流密度过大及导致散热不佳等问题,更适合应用于大电流注入的大功率LED照明。而在大电流注入时Ga N基LED会出现效率下降问题。因此,研究解决效率下降问题对提高Ga N基垂直结构LED的效率具有重要的实际意义。针对传统In Ga N/Ga N多量子阱结构中载流子分布不均匀的问题,通过APSYS仿真软件,建立了七组耦合量子阱数量不等的Ga N基垂直结构LED芯片二维模型,仿真结果表明,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匀性及空穴与电子的辐射复合率。仿真结果还表明,当耦合量子阱数量小于或等于5对时,Ga N基垂直结构LED芯片模型的有效辐射复合率、正向偏压、光输出功率均随着耦合量子阱数量的增加而大幅度改善。当耦合量子阱数量大于5对时,Ga N基垂直结构LED芯片模型的各方向特性与5对耦合量子阱模型相比均无明显提升。其中具有5对耦合量子阱的Ga N基垂直结构LED芯片模型,与只有传统量子阱的模型相比,在注入电流为350 m A时其正向偏压下降了0.46 V,光输出功率提高了39.4%。在仿真结果的基础上,利用MOCVD技术、激光剥离、电镀金属基板等技术制备了具有5对耦合量子阱的Ga N基垂直结构LED芯片样品,与只有传统量子阱的Ga N基垂直结构LED芯片相比,在注入电流为350 m A时,其正向偏压下降了0.68 V,光输出功率提升了53.0%,有更好的电流响应效率;其外量子效率下降到最大值的67.5%,而只有传统量子阱的样品下降到了37.7%,有效地缓解了大电流注入下Ga N基LEDs效率下降的问题。并通过讨论样品EL谱的变化情况,分析了耦合量子阱Ga N基LEDs在大电流下效率下降得到缓解的原因。该课题的研究结果为实现大功率LED芯片应用于通用照明领域起到了至关重要的作用。
[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.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8
本文编号：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.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN312.8
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