Electronegativity And Band Gap Of Semiconductor Materials

Functional material design has already been one of the most important research objects. This bases on a sophisticated knowledge of crystal microscopic structure and the quantitative relationship between the structure and the physical properties of crystals. For more than 70 years, electronegativity has been a fundamental parameter for the study of material properties, which is defined as an attractive ability of the atom in molecule to the electrons. Therefore, the property determined by such ability should correlate with the electronegativity. Band gap is an important parameter in determining the practical application of semiconductor materials, which denotes the required energy for an electron to jump from the valence band maximum to the conduction band minimum relating to the attractive power of bonding atoms to their valence electrons. Realizing the prediction of the parameter can provide a clue for the exploitation of new-type semiconductor materials. In this work, we investigate the band gap of semiconductor material from the viewpoint of electronegativity.In the framework of microscopic structure of materials, we analyze the origin of the band gap. Then, we propose that the band gap is determined by two factors:â…°) the attractive power of two bonded atoms to their valence electrons;â…±) the delocalization degree of the valence electrons between the two bonded atoms. From these two viewpoints, we establish a quantitative relation between electronegativity and the band gap for ANB8-N ternary compound semiconductors. Then, we extend this model to calculate the band gap of ABC2 ternary chalcopyrite compounds. The calculated band gap values of these two type compounds are in agreement with those experimental data.Doping of semiconductor is a key technology for band gap engineering, whereas a simple and effective method is imminently needed in evaluating the band gap of alloyed semiconductors. Hence, we employ our model to predict the band gaps of AxB1-xC and ABxC1-xisovalent substituted semiconductor alloys. Herein, we assume that the doped ions uniformly distribute in the host crystal. Additionally, according to whether AC and BC have the same structure, we divide these alloyed compounds into two categories. The calculated band gap results of these semiconductor alloys agree well with those available experimental data, indicating that this method gives a good description of the band gap and the covalent electronegativity can be effectively used to estimate the band gaps of semiconducting materials. This work provides us an effective method to predict the band gaps of semiconductor materials and gives guidance for the design of new alloyed semiconductors and the determination of macroscopic properties from microscopic structures.