极化效应对InGaN/GaN多量子阱结构光电特性的影响

摘要

The band structure and spontaneous emission spectra of the InGaN/GaN multiple quantum well (MQW) structures considering the polarization effect were systematically analyzed employing a newly developed theoretical model based on the k · p theory. Numerical results show that the square potential profile of conduction band and valence band change to triangle due to the polarization effect. And polarization-induced electrostatic field makes the bandgap of InGaN/GaN MQW structure narrow, which results in the red shift of peak emission wavelength. In addition, the emission efficiency of InGaN/GaN MQW structure reduces because the polarization effect separates the distribution of electrons and holes. Furthermore, the red shift of the peak emission wavelength induced by the polarization effect is enhanced under the condition of more In content in well layers or deeper well width for the InGaN/GaN MQW structures.%通过求解修正的基于k·p方法的有效质量哈密顿方程并与泊松方程进行自洽,得到在极化效应影响下InGaN/GaN多量子阱的能带结构和自发辐射谱.计算结果表明,极化效应使InGaN/GaN多量子阱结构的带边由方形势变成三角形势,使导带和价带间的带隙宽度减小导致发光峰值波长红移,并使电子和空穴的分布产生空间分离从而减小发光效率.同时,随着InGaN/GaN多量子阱结构阱层In组分的增多或阱层宽度的增加,极化效应带来的发光峰值波长红移效果进一步增强.