Theoretical study of the adsorption modes of a process control agent in the growth of PbTe (6 pages)

• H. Rojas Chávez ^[1] ; A. Miralrio ^[2] ; J.M. Juárez-García ^[3] ; H. Cruz Martínez ^[4] ; F. Montejo Alvaro ^[4]
  1. [1] Instituto Tecnológico de Tláhuac II, CDMX, México
  2. [2] Escuela de Ingeniería y Ciencias, Monterrey, México
  3. [3] Universidad Tecnológica de Querétaro, México
  4. [4] Instituto Tecnológico del Valle de Etla, Santiago Suchilquitongo, México,

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• Localización: Revista Mexicana de Física, ISSN-e 0035-001X, Vol. 71, Nº. 1, 2025
• Idioma: inglés
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• Resumen

  • The effect of formaldehyde (CH_(2)O) as a surface modifier of PbTe is evaluated. Global descriptors are calculated through density functional theory to delve into the nature of the interaction between CH_(2)O and the PbTe surface. The CH_(2)O molecule is structurally optimized using the PBE exchange-correlation functional and ultrasoft pseudopotentials. Subsequently, vertical ionization energies and vertical electron affinities are calculated to elucidate how the CH_(2)O molecule behaves energetically with respect to electron removal and gain, respectively. In order to determine regions with higher and lower charge accumulation, the electrostatic potential on the van der Waals isosurface is mapped. It is inferred that the theoretical knowledge generated is useful for proposing modes of CH_(2)O adsorption on the PbTe surface, results that rationalize the faces exposed by PbTe after surface treatment. The optimized structures of the composite systems showed a close correlation between the change in surface energy (Δγ) and the exposed faces of PbTe. Finally, through Wulff construction, the morphology of PbTe interacting with CH_(2)O as a process control agent is determined. It was found that formaldehyde helps decrease the surface energy of the exposed faces of PbTe, leading to decahedra and faceted morphologies.