A study of the inclusion of prelayers in InGaN/GaN single- and multiple-quantum-well structures

作者：Davies Matthew J^*; Dawson Philip; Massabuau Fabien C P; Le Fol Adrian; Oliver Rachel A; Kappers Menno J; Humphreys Colin J

来源：Physica Status Solidi (B) Basic Research, 2015, 252(5): 866-872.

DOI：10.1002/pssb.201451535

• GaN
• InGaN
• photoluminescence
• quantum wells
• thin films

We report on the effects on the optical properties of blue-light emitting InGaN/GaN single- and multiple-quantum-well structures including a variety of prelayers. For each single-quantum-well structure containing a Si-doped prelayer, we measured a large blue shift of the photoluminescence peak energy and a significant increase in radiative recombination rate at 10 K. Calculations of the conduction and valence band energies show a strong reduction in the built-in electric field across the quantum well (QW) occurs when including Si-doped prelayers, due to enhancement of the surface polarization field which opposes the built-in field. The reduction in built-in field across the QW results in an increase in the electron-hole wavefunction overlap, increasing the radiative recombination rate, and a reduction in the strength of the quantum confined Stark effect, leading to the observed blue shift of the emission peak. The largest reduction of the built-in field occurred for an InGaN: Si prelayer, in which the additional InGaN/GaN interface of the prelayer, in close proximity to the QW, was shown to further reduce the built-in field. Study of multiple QW structures with and without an InGaN:Si prelayer showed the same mechanisms identified in the equivalent single-quantum-well structure.

• 出版日期2015-5