Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

F De Moure-Flores,J Santoyo-Salazar,M De La L Olvera,J G Quiñones-Galván,A Guillén-Cervantes,M Meléndez-Lira,M Zapata-Torres,A Hernández-Hernández

doi:10.1063/1.4721275

F De Moure-Flores, J Santoyo-Salazar + Show 6 more

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https://doi.org/10.1063/1.4721275

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Abstract

Cu-doped CdTe thin films were prepared by pulsed laser deposition on Corning glass substrates using powders as target. Films were deposited at substrate temperatures ranging from 100 to 300 °C. The X-ray diffraction shows that both the Cu-doping and the increase in the substrate temperature promote the presence of the hexagonal CdTe phase. For a substrate temperature of 300 °C a CdTe:Cu film with hexagonal phase was obtained. Raman and EDS analysis indicate that the films grew with an excess of Te, which indicates that CdTe:Cu films have p-type conductivity.

Highlights

CdTe is a direct bandgap material with a value of 1.5 eV and an absorption coefficient >105 cm−1 in the visible region, which means that a layer thickness of few micrometers is sufficient to absorb 90% of incident photons
In this work we report on the influence of the substrate temperature on the structural and optical properties of CdTe:Cu films grown by pulsed laser deposition (PLD)
The difractogram 1c) presents three peaks located at 23.68◦, 39.26◦ and 42.64◦, the peak located at 42.64◦ corresponds to the hexagonal CdTe phase and the diffraction plane is (103)H, which indicates that probably the CdTe:Cu-200 sample has the hexagonal phase

Summary

INTRODUCTION

CdTe is a direct bandgap material with a value of 1.5 eV and an absorption coefficient >105 cm−1 in the visible region, which means that a layer thickness of few micrometers is sufficient to absorb 90% of incident photons. The maximum theoretical efficiency for a CdTe/CdS solar cell, at standard spectrum, is about 30%.2. In this system a p-type CdTe film plays the role of absorber layer. CdTe polycrystalline films can be prepared by several growth techniques such as closespace sublimation (CSS),[4] chemical deposition,[5] sputtering,[6] pulsed laser deposition (PLD),[7] vapor transport deposition (VTD), physical vapor deposition (PVD), spray deposition[1] among others. Some of these techniques, such as CSS, VTD, PVD requires a high growth temperature.

EXPERIMENTAL DETAILS

RESULTS AND DISCUSSION

CONCLUSIONS