应变纤锌矿GaN/A1_(0.15)Ga_(0.85)N柱形量子点的光学性质:流体静压力效应(英文)

Optical Properties of Strained Wurtzite GaN/Al_(0.15)Ga_(0.85)N Cylindrical Quantum Dots: Effects of Hydrostatic Pressure

在有效质量近似下,考虑强的内建电场和应变对材料参量的影响,变分研究了流体静压力对有限高势垒应变纤锌矿GaN/Al0.15Ga0.85N柱形量子点中重空穴激子的结合能、发光波长和电子空穴复合率的影响.数值结果表明,激子结合能和电子空穴复合率随流体静压力的增大而近线性增大,发光波长随流体静压力的增大而单调减小.在量子点尺寸较小的情况下,流体静压力对激子结合能和电子空穴复合率的影响更明显.由于应变效应,为了获得有效的电子-空穴复合过程,GaN量子点的高度必须小于5.5nm.

Within the effective-mass approximation,the influences of hydrostatic pressure on the exciton binding energies,emission wavelengths and electron-hole recombination rates for a heavyhole exciton in strained wurtzite (WZ) GaN/Al0.15 Ga0.85 N cylindrical quantum dot (QD) with finite potential barriers are investigated via a variational procedure,with considering the strong built-in electric field (BEF) effect and strain dependence of material parameters. Numerical results show that the exciton binding energies and electron-hole recombination rates both increase almost linearly,and the emission wavelengths are monotonically reduced with the increase of the applied hydrostatic pressure.The hydrostatic pressure has a remarkable influence on the exciton binding energy and electron-hole recombination rate for the QD with a small size.Furthermore,the height of GaN QDs must be less than 5.5 nm for an efficient electron-hole recombination process due to strain effects.