Design of $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructures using glancing angle deposition technique for enhanced photodetection

Abstract

Glancing angle deposition technique was employed to fabricate $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure on n-type Si substrate. The X-ray diffraction analysis depicts that the $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure was polycrystalline in nature. Higher photoluminescence intensity was obtained for $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure as compared to bare $$\text {SnO}_{2}$$ nanowires, due to the higher junction area between two layers and higher electron–hole pair generation. The photodetectors fabricated using $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure showed averagely 2.3 times higher photoresponse as compared to bare $$\text {SnO}_{2}$$ nanowire photodetector at $$-2$$ V. The enhanced photoresponse for $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure was described with reference to the interface junction. A high responsivity of 16.43 A/W and high detectivity of $${2.58}\times {10}^{{12}}$$ jones with noise equivalent power as low as $${1.085}\times {10}^{-12}$$ W were obtained for $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure. Moreover, the current conduction mechanism of $$\text {Er}_{2}\text {O}_{3}$$-capped $$\text {SnO}_{2}$$ nanostructure was explained with the help of the band diagram.