A comparative study of photoconductivity in LaTiO_3/SrTiO_3 and LaAlO_3/SrTiO_3 2-DEG heterostructures

摘要

Here we compare the growth temperature dependence of the response of LaTiO_3/SrTiO_3 and LaAlO_3/SrTiO_3 2D-electron gas (2-DEG) field effect structure to the optical radiation of near ultraviolet frequency and electrostatic gate field. For both the films the resistance of the channel increases significantly as growth temperature is lowered from 800 to 700 °C. These heterostructures show the photoconductivity (PC) simulated by UV light of λ ≤ 400 nm. The PC follows the stretched exponential dynamics. It is found that photo-response of the LaTiO_3 films is prominent and has larger decay time constant as compare to LaAlO_3 films. The effect of electric field on the photo-induced conducting state is also studied.