Terahertz Emission and Ultrafast Carrier Dynamics of Ar-Ion Implanted Cu(In,Ga)Se2 Thin Films

Chul Kang,Dae-Hyung Cho,Yong-Duck Chung,Inhee Maeng,Chul-Sik Kee,Gyuseok Lee,Woo-Jung Lee

doi:10.3390/cryst11040411

Abstract

We investigated THz emission from Ar-ion-implanted Cu(In,Ga)Se2 (CIGS) films. THz radiation from the CIGS films increases as the density of implanted Ar ions increases. This is because Ar ions contribute to an increase in the surface surge current density. The effect of Ar-ion implantation on the carrier dynamics of CIGS films was also investigated using optical pump THz probe spectroscopy. The fitted results imply that implanted Ar ions increase the charge transition of intra-and carrier–carrier scattering lifetimes and decrease the bandgap transition lifetime.

Highlights

Copper indium gallium diselenide (CIGS) thin films are considered good candidates for semiconductor-based solar cells, because they are capable of large-area fabrication and have a high energy conversion efficiency and flexibility
To radiate the THz waves on the CIGS thin films, a femtosecond laser with an 80 MHz repetition rate, 800 nm wavelength, and 100fs pulse width was illuminated on the samples
The spectral amplitudes of the CIGS thin films increase as the Ar-ion implantation density increases

Summary

Introduction

Copper indium gallium diselenide (CIGS) thin films are considered good candidates for semiconductor-based solar cells, because they are capable of large-area fabrication and have a high energy conversion efficiency and flexibility. They are extensively used in the space of solar cell applications in particular, owing to their flexibility and large-area fabrication [1,2,3,4]. Ion implantation is an extremely useful tool, for controlling the electrical properties of semiconductor surfaces [7]. It can be utilized as an alternative to adjust the electrical and optical properties of semiconducting thin film materials such as CIGS. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations

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Conclusion