Fowler–Nordheim Current Oscillations in Si(111)/SiO₂/Twisted-Si(111) Tunneling Structures

Abstract

AgGaS 2 (AGS) single crystals grown by chemical vapor transport (CVT) method were irradiated with Ag 9+ ions (120 MeV) with various ion fluences. The irradiation was carried out at room temperature (RT) and at liquid nitrogen temperature (LNT). A glancing angle x-ray diffraction (GAXRD) analysis reveals a huge lattice disorder at RT irradiation. This is observed from an increase in the full width at half maximum (FWHM) and a decrease in the intensity of the AGS (1 1 2) peak. However, there is no change in the FWHM of the (1 1 2) peak but the intensity slightly decreases at LNT irradiation. Also, AGS (3 0 3) peak is not observed for the samples irradiated with the fluences of 5 × 10 13 and 1 × 10 13 ions cm −2 at RT conditions. The GAXRD results show the decrease in degree of crystallinity upon ion irradiation at RT while there is not much degradation in crystallinity upon ion irradiation at LNT. But the LNT irradiation on AGS has its own effects. Atomic force microscope (AFM) studies show that the roughness of AGS increases on increasing the ion fluences at LNT and at RT. Also, it is found that there is an increase in the surface defects with fluences of Ag 9+ ion irradiation when compared to pristine AGS. UV-visible transmission spectra show that the percentage of transmission and bandgap energy decrease with increasing ion fluences and also that the peaks are broadened at LNT and at RT. The photoluminescence (PL) spectra were analyzed as a function of irradiation ion fluences in the AGS crystals at RT. It has been found that the emission intensities of band-to-band transition decrease with increase of ion fluences at LNT and at RT.