p-AlGaN电子阻挡层Al组分对Si衬底绿光LED性能影响的研究

p-AlGaN electron blocking layer with different Al fractions on green InGaN/GaN LEDs grown on Si substrates

在Si(111)衬底上利用MOCVD方法生长了具有不同Al组分p-AlGaN电子阻挡层的绿光InGaN/GaN LED结构,并对其光电性能进行了研究.结果表明,不同Al组分样品的量子效率随电流密度的变化规律呈现多样性.在很低电流密度范围,LED量子效率随Al组分升高而下降;在较高电流密度范围,LED量子效率随Al组分升高而升高,即此时缓解了量子效率随电流密度增大而衰退的速率(即droop效应);但随着电流密度的进一步升高,反而加快了量子效率衰退的速率.这些现象解释为不同Al组分的p-AlGaN对空穴和电子注入到量子阱进行复合的机理存在差异所致.

We grow green light emitting diodes （LEDs） on Si（111） substrates with p-AlGaN electron blocking layers （EBLs） which have different Al frations.The results show that the variation of quantum efficiency with current density displays a diversity.At lower current densities,the quantum efficiency of LED increases with Al fraction decreasing,at higher current densities,however,the quantum efficiency of LED increases with Al fraction decreasing,which is attributed to the complicated mechnism when electron and hole are recombined in the quantum well.