Open AccessGrain/grain‐boundary mediated dispersive photo‐current characteristics in close space sublimated micro‐granular CdTe films
Author(s) -
Ramanathan Kulandai Velu,
Shankar Balakrishnan,
Nair Shantikumar V.,
Shanmugam Mariyappan
Publication year - 2020
Publication title -
iet optoelectronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.379
H-Index - 42
eISSN - 1751-8776
pISSN - 1751-8768
DOI - 10.1049/iet-opt.2019.0142
Subject(s) - materials science , grain boundary , cadmium telluride photovoltaics , current (fluid) , grain size , optoelectronics , composite material , physics , microstructure , thermodynamics
Photo‐current characteristics in close space sublimation processed multi‐facetted Cadmium Telluride (CdTe) micro‐granular films were studied under AM1.5, blue and green laser illuminations to assess the energy dependent charge transport characteristics. Photo‐current under AM1.5 illumination (100 mW/cm 2 ) resulted in three times more than dark current while it was observed 2.4 and 2.5 times more in case of blue and green laser illuminations, respectively. While all the three illuminations (AM1.5, blue and green lasers) were capable to generate photo‐electrons in CdTe, the variation in magnitude was articulated to the effect of grain boundaries present across the charge transport pathways as evidenced from the surface morphology examined by scanning electron microscopic studies which asserted that CdTe films were micro‐granular in nature separated by grain boundaries. It is elucidated in the measurements that charge carriers under the illumination of AM1.5 light, acquired energy to overcome the grain boundaries easily compared to the charge carriers produced by blue and green light sources as evidenced from the photo‐current measurements.