Abbassi A, Zarhri Z, Azahaf Ch, Ez-Zahraouy H, Benyoussef A
Laboratory of Magnetism and High Energy Physics (URAC 12), Faculty of Sciences, Mohammed V University, B.P. 1014, Rabat, Morocco.
Springerplus. 2015 Sep 24;4:543. doi: 10.1186/s40064-015-1321-z. eCollection 2015.
The electronic and optical properties of CdSe in two phases, cubic and wurtzite, have been studied by first principal calculations using the density functional theory. The optical parameters such as transmittance, optical absorption, refractive index and extinction coefficient have been investigated. We have calculated also the band structure, and total/partial density of state using the full potential-linearized augmented plane wave method with the local density approximation, generalized gradient approximation and the modified Becke-Johnson functional (mBJ), implemented in the Wien2k package. With the mBJ approximation the gap found for cubic and wurtzite structure is direct and is equal to 1.85 and 1.7 eV respectively, what corresponds to the experiment results. The optical absorption is significant in the ultraviolet field while it becomes low beyond 600 nm in the visible light for CdSe in different structures. From λ = 400 nm the transmittance is stable and reaches 80 %. With Boltztrap package, we have investigated also that with increasing temperature, the electrical conductivity increases. During the calculation, the cubic structure has presented an isotropy. While for wurtzite CdSe, the propagation of waves into system is different in xx and zz directions. These results can be exploited in several applications of CdSe in optoelectronic devices.
利用密度泛函理论通过第一性原理计算研究了立方相和纤锌矿相CdSe的电子和光学性质。研究了诸如透射率、光吸收、折射率和消光系数等光学参数。我们还使用全势线性缀加平面波方法，在Wien2k软件包中实现的局域密度近似、广义梯度近似和修正的Becke-Johnson泛函（mBJ），计算了能带结构以及总态密度和分态密度。采用mBJ近似时，立方相和纤锌矿相结构的能隙均为直接能隙，分别等于1.85和1.7 eV，这与实验结果相符。对于不同结构的CdSe，光吸收在紫外区域显著，而在可见光中超过600 nm时变得很低。从λ = 400 nm起，透射率稳定并达到80%。使用Boltztrap软件包，我们还研究了随着温度升高，电导率增加。在计算过程中，立方相结构呈现各向同性。而对于纤锌矿相CdSe，波在xx和zz方向上向系统中的传播是不同的。这些结果可用于CdSe在光电器件中的多种应用。
