Photovoltaic effects in obliquely deposited oxygen-deficient manganite thin film

Abstract

Photovoltaic effects have been observed in oxygen-deficient La0.6Ca0.4MnO3−δ thin film obliquely deposited on Si substrate. The oxygen vacant sites can raise the photovoltaic sensitivity of the manganite thin film, and the photovoltaic sensitivities of 33.4V∕W and 2.84×105mV∕mJ are observed when the film is irradiated by a 635nm continuous wave laser and by a 532nm pulsed laser of 7ns duration, respectively. The open-circuit photovoltage of the film, when irradiated by the pulsed laser, has an abnormal change with a fast positive response of about 17ns and the change of voltage polarity after the laser pulse. It is found that the thickness of the film has important effects on the photoelectric characteristics and the abnormal photovoltage comes from the thickness difference.