Energy Band Structure of Zn3P2-Type Semiconductors: Analysis of the Crystal Structure Simplifications and Energy Band Calculations

The simplifications of the Zn3P2-type crystal structure having tetragonal symmetry D4h15 have been analysed. After description of the real unit cell the following simplifications are proposed: tetragonal symmetry (ideal and D4h17), cubic symmetry and the correct molecular ratio (approximations Oh9, Th7 and Oh4) and finally the zincblende and antifluorite approximations. In the second part we present the results of energy band calculations for fully symmetric Zn3P2 and for all the simplifications. The symmetry of bands is also determined for the full crystal structure and for the ideal approximation. In the calculations the nonlocal empirical pseudopotential method has been used.