Negative photoconductivity and infrared quenching effects in rare-earth-doped n-InSe

The features of negative photoconductivity, background illumination-induced impurity photoconductivity, optical quenching of intrinsic photoconductivity in pure and rare-earth (REE) doped n-InSe crystals were studied in order to identify new possibilities for practical application in optoelectronics. At low concentrations (N REE <1.0 at.%) of REEs influence the degree of spatial inhomogeneity in the studied samples without inducing intra-center effects, which at higher concentrations can significantly affect their electrical, luminescent, and photoelectric properties. The research focuses on rare-earth elements such as holmium (Ho) and erbium (Er), introduced at varying concentrations (N REE =10 -5 -10 -1 at.%) into n-InSe crystals (n-InSe<Ho> and n-InSe<Er>). This selection of materials enables a comparative analysis of the experimental results to determine the dependence of the observed photoelectric phenomena on both the concentration and the chemical nature of the REE dopant. Based on a comprehensive set of experimental studies, the feasibility of developing highly sensitive, next-generation tandem infrared (IR) photodetectors has been demonstrated. These detectors, based on n-InSe<Ho> and n-InSe<Er> crystals with REE concentrations in the range 5·10 -2 ≤N≤10 -1 at.%, operate effectively within the optical spectral ranges of 1.20-1.90 µgm and 2.00–3.60 µgm.