InxGa1-xAs/GaAs量子阱应变量对变温光致发光谱的影响

利用变温光致发光(PL)研究了In0.182Ga0.818As/GaAs应变及应变补偿量子阱在77～300 K温度范围内的发光特性.随着温度T的升高,PL峰位向低能方向移动.在应力作用下In0.182Ga0.818As/GaAs量子阱的价带顶轻空穴带和重空穴带发生了劈裂.通过理论计算推导应变随温度变化对InxGa1-x...

Strain Effect on Temperature Dependent Photoluminescencefrom In_xGa_(1-x)As/GaAs Quantum Wells

The variable-temperature photoluminescence (PL) spectra of In_0.182Ga_0.818As/GaAs strained and strain-compensation quantum wells (QWs) were experimentally determined in the temperature range of 77~300 K. The PL peak positions shift to lower energies with the increasing temperature. Strain which is induced by lattice mismatch between epitaxial layer and substrate removes the degeneracy between the light-hole and heavy-hole states at the top of the valence band. A theoretical calculation was presented that takes into account the temperature-induced variations in band gap and biaxial strain to explain the PL spectra.Based on the Varshni relationship, the change of the band gap energy caused by the strain was introduced. It is the function of the temperature and the alloy composition. The calculated results are agree with the experimental data. The full-width at half-maximum (FWHM) of PL spectra of In_0.182Ga_0.818As/GaAs strained three quantum wells is larger than that of strain-compensation one, and increases more quickly, which is caused by exciton-LO phonon coupling. At last, strain effect on the PL spectra was confirmed through the FWHM curve at various temperature.