Analysis on the structural, vibrational and defect states of chlorine treated polycrystalline cadmium telluride structures grown by e-beam evaporation. (5th February 2015)

• Record Type: Journal Article
• Authors: Farid, Sidra; Mukherjee, Souvik; Jung, Hyeson; Stroscio, Michael A; Dutta, Mitra
• Is Part Of: Materials research express. Volume 2:Number 2(2015)
• Publication Date: 2015-02-05
• Subjects: polycrystalline CdTe -- chlorine treatment -- materials characterization; Materials science -- Research -- Periodicals; Materials science -- Periodicals; 620.11
• DOI: 10.1088/2053-1591/2/2/025007
• Languages: English
• ISSNs: 2053-1591

Abstract

Abstract: Temperature dependent photoluminescence (PL) measurements are performed in order to study the defect states in cadmium chloride treated polycrystalline cadmium telluride (CdTe) thin films grown by e-beam evaporation technique. Three luminescence bands are observed including a double peak emission at 1.577 eV and 1.573 eV corresponding to free electron-to- acceptor transition and a donor–acceptor pair (DAP) transition, respectively, along with a broad peak at 1.45 eV. This broad band emission is related to A-center chlorine based complex and also includes longitudinal (LO) phonon emission lines for CdTe spaced by ∼21 meV. Investigation into grain sizes revealed grains of 0.2 μ m for as-grown films and ∼2–3 μ m for chlorine activated films shown by atomic force microscopy (AFM). Raman analysis indicates that the films have been grown with excess of Te leading to p-type conductivity in the structure, whereas LO phonon mode of polycrystalline CdTe reveals quasi phonon modes nature.