Multi-functional platform based on amorphous Ge2Sb2Te5 thin films for photo/thermodetection and non-volatile memory applications

Abstract

As a result of the copious interest and development in multifunctional electronics, the need for a multifunctional platform with a stable and unique performance has become one of the most important research concerns. In this embodiment, the amorphous Ge2Sb2Te5 (a-GST) thermally evaporated phase-change thin films are utilized for photo/thermodetection applications. The structural, compositional, and topographical methodologies confirm the amorphous nature with smooth surface topology and average particle size of about 31 ± 10 nm. Furthermore, the optical properties of the deposited a-GST revealed the broadband absorption spectrum with indirect energy gap and Urbach energy of about 0.54 eV and 380 meV, respectively. Furthermore, the dispersion and electronic parameters of the deposited films are determined. The switchable resistivity properties of Au/a-GST/Au are evaluated, and the phase change transition is observed in the temperature range (413–463) K. Moreover, the microelectronic parameters and interface features, in addition to the charge carriers' dynamics in the fabricated Ag/a-GTS/n-Si/Au–Sb heterojunction, are interpreted and analyzed in detail. Besides, the thermodetection capability of the fabricated heterojunction is evaluated in the temperature range (303–573) K. The estimated values of the thermosensitivity of about – (28.02 ± 1) and – (3.60 ± 0.13) mV/K at driving activation current of 600 μA for the two phases regions, respectively. Additionally, the photodetection performance of the implemented architecture is tested under halogen illumination of intensity (20–100) mW/cm2. The fabricated device shows a remarkably stable light signal response with responsivity, specific detectivity, and trise/tfall of about 203.1 mA/W, 2.84 × 109Jones, and 267 ms/84 ms, respectively. Ultimately, based on the recorded results, the Au/a-GST/n-Si/Au–Sb heterojunction is suggested for multifunctional applications with promising performance.