激发功率密度和阱层厚度对极化InGaN/GaN多量子阱光致发光性能的影响

用MOCVD技术在c面蓝宝石衬底上生长了具有不同阱层厚度的InGaN/GaN多量子阱结构,研究了阱层厚度和激发功率密度对多量子阱光致发光(PL)性能的影响.结果表明,随着激发功率密度的增加,PL的峰值波长会出现不同程度的蓝移,且阱层越厚,蓝移的越明显.PL的峰值波长随着激发功率密度和阱厚的变化关系可以用光生载流子对极化场的屏蔽效应和带隙填充效应来解释.阱最薄的样品(1.8 nm)由于其极化效应最弱,电致发光谱具有最高的发光强度,但其发光波长较短仅有430 nm.

Effect of Excitation Power Density and Well Thickness on Photoluminescence Properties of InGaN/GaN Multiple Quantum Well

The growth of InGaN/GaN multiple quantum wells with different well thickness grown on cplane sapphire substrate by MOCVD was reported.The dependence of photoluminescence on excitation power density and well thickness was obtained.All samples exhibited an excitation-induced blueshift of the peak emission with the increase of excitation power density,and a larger blueshift of MQWs with wider well was measured.The shift of PL peak position with increasing excitation power density and well thickness can be clarified by the model of band filling effect and shielding of built-in field.The thinnest well LED sample (1.8 nm) has the highest optical output power,which is due to the weakest built-in field,however,its emitting wavelength is only 430 nm.