We present a study of the electronic and optical properties of carriers in GaAs/Al_xGa_1-xAs quantum ring (QR) as a function of the aluminum concentration (x) in the barrier and the ring height (h_M). We calculated the wavefunctions and the energies of the electrons and holes using the effective mass approximation. We found that the variation of x or h_M, leads to a crossover, and consequently the mixing, of the electronic states of symmetry X and Γ. Then, a change from type I to type II of the GaAs/AlGaAs quantum ring occurs for x about 0.6 and h_M about 1.3 nm. To present the point of type I-type II transition, we drew a color map that shows the shift of this point with x and h_M. The radiative lifetime of the carriers is calculated in both type I and type II cases. In the latter case, we have taken into account the coupling between the confined electronic states of symmetry X and Γ. A value of 7 meV for the coupling potential is deduced from a comparison between our theoretical results and experimental ones. A color map showing the variation of the lifetime with x and h_M was likewise drawn. Finally, these results can be exploited in several applications like solar cells.

我们目前对GaAs / Al _x Ga _1-x As量子环（QR）中的载流子的电子和光学性质的研究，它是势垒中铝浓度（x）和环高度（h _M）的函数。我们使用有效的质量近似值计算了电子和空穴的波函数和能量。我们发现x或h _M的变化会导致对称X和Γ的电子状态发生交叉，从而导致混合。然后，对于大约0.6的x和大约1.3nm的h _M，发生GaAs / AlGaAs量子环的从I型到II型的变化。为了显示I型到II型过渡点，我们绘制了一个颜色图，该图显示了该点在x和h _M处的位移。在I型和II型情况下都计算了载流子的辐射寿命。在后一种情况下，我们考虑了对称电子X和Γ的受限电子状态之间的耦合。通过将我们的理论结果与实验结果进行比较，得出耦合电位的值为7 meV。同样绘制了显示寿命随x和h _M变化的色图。最后，这些结果可以在太阳能电池等多种应用中得到利用。