access icon free Grain/grain-boundary mediated dispersive photo-current characteristics in close space sublimated micro-granular CdTe films

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/cm2) 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.

Inspec keywords: grain boundaries; semiconductor thin films; photoconductivity; sublimation; II-VI semiconductors; cadmium compounds; granular materials; scanning electron microscopy; surface morphology

Other keywords: surface morphology; grain-boundary mediated dispersive photocurrent characteristics; CdTe; green laser illuminations; blue light sources; blue laser illuminations; close space sublimated microgranular CdTe films; charge transport pathways; energy dependent charge transport characteristics; AM1.5 light illumination; photocurrent measurements; scanning electron microscopy; green light sources; photoelectron generation; multifacetted cadmium telluride microgranular films; charge carriers

Subjects: Photoconduction and photovoltaic effects; photodielectric effects; Photoconducting materials and properties; II-VI and III-V semiconductors; Solid surface structure; Electrical properties of II-VI and III-V semiconductors (thin films, low-dimensional and nanoscale structures); Thin film growth, structure, and epitaxy; Grain and twin boundaries

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