The innovation engine for new materials

Arlette Valencia

Arlette Valencia lab photo


Electrical Engineering


Oregon Institute of Technology Wilsonville


Omor Shoron

Faculty Sponsor(s): 

Susanne Stemmer

Faculty Sponsor's Department(s): 


Project Title: 

The Effect of Sn/Ba Ratio in Molecular Beam Epitaxy on Thin Film Electrical Properties

Project Description: 

Wide bandgap materials have become a focus in electronics applications because of their prospective capacity to perform at high power and high frequencies all the while being optically transparent. BaSnO3 (BSO) is one such material that has demonstrated high mobility both in single crystal bulk (320 cm2/V-s) and thin films (175 cm2/V-s) despite being highly doped. To increase its mobility further, it can be implemented in a heterostructure for modulation doping.  High quality thin films are needed for developing these heteorstructures which is why molecular beam epitaxy (MBE) is used. MBE allows for high resolution control of crystal growth with material depositing on the substrate layer by layer at atomic thinness. Previous research has shown that using SnO2 for the Sn source in MBE produces higher quality thin films which suggests that the Sn/Ba ratio may also play a role. Several films were grown with varying Sn/Ba ratios for different times to control film thickness. X-ray diffraction (XRD) indicates the film thickness and the lattice constant thus, revealing the structural quality of the grown thin films. Hall measurements were taken to get the mobility for most films. Atomic force microscopy (AFM) was used to determine surface smoothness. The XRD analysis and Hall measurements showed the effect of Sn/Ba ratio on the growth rate and mobility. The film thickness was also shown to affect the mobility, so more consistent film thicknesses can be obtained using the growth rates found for each Sn/Ba ratio. There will be greater control in growing BSO thin films in MBE with this information.