Correlation between electrical and compositional properties in cadmium sulfide deposited by laser ablation

This work reports the correlations between electric and compositional properties of thin CdS films deposited by pulsed laser deposition (PLD), which underwent pressures from 2.66 to 10.66 Pa using argon as inert gas. The films were deposited on substrates of glassy carbon and SiO2 and characterized by Rutherford backscattering spectrometry, as well as van der Pauw and Hall measurements. Excess of cadmium in the deposited films at the lower pressures was observed, presumably from the CdS target, which resulted from the self-sputtering effect during PLD. Electrical characterization showed N-type behavior and resistivity decreasing proportional to the excess of cadmium in the films. The measured band gap after the deposition did not change from the initial 2.42 eV. Resistivity, charge carrier concentration and mobility ranged between (10(-1)-10(4)) Omega.cm, (10(19)-10(13)) cm(-3) and (2-12) cm(2).V-1.s(-1), respectively. These results confirm the relevance of point defects and oxygen in the electrical properties of CdS indicating the possibility of controlling electrical response from deposition pressure.