The First Principle Research Of Infrared Photonelectric Material PbS

The IV-VI narrow-gap semiconductor PbS is one of the focus and the difficulty both theory and experiment of infrared area owing to its unique character applied in infrared detector, laser diode, hermoelectric materials and long distance fiber optics.With the development of computer science, it has been more and more popular to use the first principle method to calculate narrow gap semiconductor in the electronic structure and the effect of doping and defect. On one hand, the result is the gist on experiment and material synthesize. On the other hand, the calculation could also help to explain experimental new discoveries theoretically. In this way, we could optimize the experimental ways and make the prediction as well. This do benefit the development of narrow gap semiconductors materials and devices on theory.In the present thesis, we have calculated the electronic structure of PbS by the first principle method, the primary content of this thesis is composed the following three parts: 1) Based on the full potential linearized plane wave method of first principle, the calculations of the total energy and the equilibrium lattice constant for the fcc PbS(NaCl) compound have been performed within different exchange-correlation potentials (DECP) on both the generalized gradient approximation (GGA) and the local density approximation (LDA). The effects of DECP on the equilibrium lattice constant are discussed. The band structure, energy gap, the density of states and the partial density of states in the case of equilibrium are analyzed.2) Like the NaCl structure PbS, we also calculate the total energy and the equilibrium lattice constant for the PbS (CsCl) compound within different exchange-correlation potentials based on the full potential linearized plane wave method of first principle. The effect of DECP on the band structure, the density of states, the partial density of states and the band gap are discussed, respectively. The energy calculation shows that the NaCl structure is found to be the more stable one than that of the CsCl structure. In addition, band structure calculations in the CsCl structure show a band-gap existence, which agrees well with experimental results of other Pb chalcogenide compound (PbTe). The above result of PbS (CsCl) is helpful to the experimental study in the future.3) Finally, a brief conclusion of our work was given.