Outstanding improvement in ultraviolet photodetection with DyCrO3/n-Si heterojunction device on manganese substitution

Abstract

The influence of manganese (Mn) substitution on the ultraviolet (UV) photodetection of DyCrO₃/n-Si device has been investigated. DrCr_1-xMn_xO₃ (x = 0, 0.2, 0.5) thin films were deposited on n-type silicon substrate utilizing the spin-coating method. XRD patterns confirmed the substitution of Mn-ions at Cr-site in DyCrO₃ lattice. Current voltage (I–V) characteristics of the fabricated devices exhibited a diode-like behaviour. Moreover, I–V behaviour of the films followed the trap-assisted tunnelling (TAT) and space-charge-limited conduction (SCLC) mechanisms at lower and higher electric fields, respectively. Transient photocurrent measurements were performed on the fabricated films by exposing them to UV radiation of wavelengths 365 and 254 nm and an on/off cycle of 20 s. Notably, the UV sensitivity increased from 142% for DyCrO₃ (DCO) to 429% for DyCr_0.5Mn_0.5O₃ (DCMO50) heterojunction device. The produced devices exhibited a significant increase in responsivity from 7.81 × 10^–4 mA/W to 1.01831 mA/W with a corresponding increase in Mn concentration from 0% to 50 at. %. The fabricated devices also demonstrated an enhancement in detectivity and external quantum efficiency (EQE) values. The detectivity increased from 0.807 × 10¹⁰ cmHz^1/2/W (0% Mn) to 1.11 × 10¹⁰ cmHz^1/2/W (50% Mn), while EQE values arose from 2.65 × 10^–4% (0% Mn) to 0.34% (50% Mn). The increase in Mn concentration also led to an increment in the linear dynamic response (LDR) value, elevating it from 7.47 dB to 10.36 dB. The significant improvement in UV detection parameters with Mn substitution is advantageous in designing UV photodetectors with enhanced efficiency.