A newly NaCaSm(BO3)2 interfacial material doped with rare-earth ions for sensitive photo-detection in Schottky structures

In this study, NaCaSm(BO3)2, a rare earth element-based borate compound that can be synthesized at room temperature and at low cost, is presented as a novel interface material. Using this material, NaCaSm(BO3)2/n-Si and NaCaSm(BO3)2/p-Si structures were produced, and the photodiode performances of these devices were investigated to elucidate the relationship between the properties of borate compounds and optoelectronic applications. Current-voltage characteristics revealed that the devices efficiently produced photocarriers under illumination, and the carrier density increased with increasing light intensity. Double logarithmic photocurrent analyses showed that local interface state distributions and low-density trapping mechanisms were effective in devices. Significant increases in responsivity and sensitivity values were obtained with increasing illumination intensity. Furthermore, achieving a high detector sensitivity of 1.43 × 10¹¹ Jones even under the lowest illumination conditions demonstrates the devices’ superior performance with weak optical signals. The devices produced stable and reproducible photocurrent responses. Wavelength-dependent measurements revealed that both structures exhibited a strong photoresponse across a wide spectral range. These findings indicate that the fabricated devices, with their low-power, wideband, and high-sensitivity characteristics, as well as their ability to operate across a broad spectrum from ultraviolet to infrared, are candidates for next-generation circuit elements in opto-electronic applications.