Urbach”™s tail in indirect band-gap semiconductors

Larissa Durán Flores, Gerardo Fonthal


In this work, the band tail parameters in GaP, Ge and Si, indirect band gap semiconductors, have been studied using the published data. It is established that the optical absorption edge in these materials obeys Urbach”™s Rule. It is also found that the structural disorder in monocrystalline materials is around zero, due to the natural disorder of the crystal lattice. The width of the exponential tail or Urbach”™s energy is found between 20 and 39meV at 77K and 60-70meV at 300K. Also, the steepness parameter s is above 0.55, indicating a strong phonon interaction typical in indirect band gap semiconductors.

Palabras clave

indirect band gap; optical absorption; band tails; Urbach”™s rule

Texto completo:


Universidad del Zulia /Venezuela/ Revista Técnica de la Facultad de Ingeniería/ revistatecnica@gmail.com /

p-ISSN: 0254-0770 / e-ISSN: 2477-9377 


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