Pulsed laser-induced crystallization of amorphous Cu₂O thin films for enhancedelectro-optical properties and advanced communication technologies

Herein, amorphous copper oxide thin films are irradiated with laser pulses of various pulse widths (PW) and repetition frequencies (f_R) to achieve ultrafast crystallinity and obtain enhanced features suiting electro-optical systems. Pulsed laser irradiated (PLI) films exhibited crystalline orthorhombic-hexagonal structure when irradiated with PW of 5.0 ms and f_R=1.0 Hz and preferred the hexagonal structure as a major phase at PW value of 50.0 ms and f_R=1.0 Hz. The crystallinity is enhanced with increasing PW and f_R values. Films irradiated with pulsed laser of f_R=1.0 Hz exhibited interesting morphology presented by growth of nano-grains at PW=5.0 ms that converts to textured microspheres at PW=50 ms. Optically, the films transmittance increased and reflectance decreased with increasing PW value leading to widening of the energy band gap for most of the irradiated films. The PLI films were used for the design of planner waveguides suitable for global system for mobile communications technology showing negative capacitance effect and excellent impedance match and signal transfer properties presented by return loss value of 29 dB and reflection coefficient value of 0.036 at quad band frequency of 1800 MHz. These ideal features of the PLI films make them suitable for applications concerned communication technology.