Bias voltage controlled photoluminescence from β-In 2S 3 thin films

Abstract

β-In 2S 3 thin films were deposited on Indium Tin Oxide substrates using the Chemical Spray Pyrolysis technique. Metal contact was deposited over the β-In 2S 3 thin film to form a hetero-structure of the type ITO/ β-In 2S 3/Metal. The intensity of two photoluminescence emissions from the β-In 2S 3 thin film, centered at 520 and 690 nm could be varied by the application of an external bias voltage to this hetero-structure. The emissions could be switched on or off depending upon the magnitude of the external applied bias voltage. Thus the presence of two conducting states in this hetero-structure could be identified. The temporal variation in intensity of the photoluminescence emission with the application of the bias voltage has also been studied. The condition under which photoluminescence quenching occurs has been represented by a first order differential equation between diffusion length and carrier concentration.