Mahendra, K.Maria Fernandes, J.Udayashankar, N.K.2026-02-042022Radiation Effects and Defects in Solids, 2022, 177, 46304, pp. 928-94210420150https://doi.org/10.1080/10420150.2022.2098744https://idr.nitk.ac.in/handle/123456789/22768The structural, optical, mechanical and electrical properties of pure and 5—20-kGy gamma-irradiated semi-organic single crystals of ammonium hydrogen oxalate oxalic acid dihydrate (NH<inf>4</inf>H<inf>3</inf>(C<inf>4</inf>O<inf>8</inf>).2H<inf>2</inf>O) are presented. The crystals were synthesized at room temperature using facile solvent evaporation technique. Powder XRD measurements indicate gradual enhancement in crystallinity and lattice defect annihilation for low radiation dosage. Radiation-induced increase in optical band gap (4.01–4.16 eV) indicates high damage threshold of the crystals. Quenching of photoluminescence is attributed to the lowering of surface defect density with radiation. The influence of gamma radiation on the functional vibrations of the crystals is studied using FTIR-Raman spectroscopy. Vickers microhardness measurements show gradual enhancement in crystal hardness with the increase in radiation. An increase in forward resistance with irradiation is observed from I–V measurements and is attributed to high transparency of the crystals. These results indicate the viability of NH<inf>4</inf>H<inf>3</inf>(C<inf>4</inf>O<inf>8</inf>) 2H<inf>2</inf>O crystals in potential space optoelectronic applications. © 2022 Informa UK Limited, trading as Taylor & Francis Group.CrystallinityEnergy gapFourier transform infrared spectroscopyHydrogenIrradiationOxalic acidPhotodegradationSingle crystalsSurface defectsAmmonium hydrogen oxalate oxalic acid dihydrateDefect annihilationDefects inducedGamma irradiationMeasurements ofMechanical and electrical propertiesOptoelectronic applicationsOxalic acid dihydrateSemi organicSpace optoelectronic applicationGamma rays