Novel BTlGaN semiconducting materials for infrared opto-electronic devices

Abstract

BTlGaN quaternary alloys are proposed as new semiconductor materials for infrared opto-electronic applications. The structural and opto-electronic properties of zinc blende BxTlyGa1−x−yN alloys lattice matched to GaN with (0⩽x and y⩽0.187) are studied using density functional theory (DFT) within full-potential linearized augmented plane wave (FP-LAPW) method. The calculated structural parameters such as lattice constant a0 and bulk modulus B0 are found to be in good agreement with experimental data using the new form of generalized gradient approximation (GGA-WC). The band gaps of the compounds are also found very close to the experimental results using the recently developed Tran–Blaha-modified Becke–Johnson (TB-mBJ) exchange potential. A quaternary BxTlyGa1−x−yN is expected to be lattice matched to the GaN substrate with concentrations x=0.125 and y=0.187 allows to produce high interface layers quality. It has been found that B incorporation into BTlGaN does not significantly affect the band gap, while the addition of dilute Tl content leads to induce a strong reduction of the band gap, which in turn increases the emission wavelengths to the infrared region. The refractivity, reflectivity and absorption coefficient of these alloys were investigated. BTlGaN/GaN is an interesting new material to be used as active layer/barriers in quantum wells suitable for realizing advanced Laser Diodes and Light-Emitting Diodes as new sources of light emitting in the infrared spectrum region.