ZnS thin films are deposited on porous silicon (PS) substrates with different porosities by pulsed laser deposition (PLD). The photoluminescence (PL) spectra of the samples are measured at room temperature. The results show that the PL intensity of PS after deposition of ZnS increases and is associated with a blue shift. With the increase of PS porosity, a green emission at about 550 nm is observed in the PL spectra of ZnS/PS systems, which may be ascribed to the defect-center luminescence of ZnS films. Junction current-voltage (I-V) characteristics were studied. The rectifying behavior of I-V characteristics indicates the formation of ZnS/PS heterojunctions, and the forward current is seen to increase when the PS porosity is increased.
© 2009 Chinese Optics LettersPDF Article