The dependence of fractal figures formed in irradiated germanium on temperature and composition

Abstract

D C conductivity (σ) measured in the temperature (T) range (300 K–1.7 K) for p-Type Ge irradiated with γ quanta and /or large fluencies of reactor neutrons. The obtained conductivity results reveal that, the activation energies of different conductivity mechanisms are found E1 > E2 > E3 and σo > σ1 > σ2. Also, Meyer- Neldel Rule (MNR) is applicable in different conduction mechanisms. As well as, in hopping conduction mechanisms with different values of Meyer-Neldel Energy (HMNR) for each conductivity mechanism. Mott variable range hopping (VRH) σ = f (T−0.25), and Efros Sholovskii Percolation mechanism of conduction (ESPMC) σ = f (T−0.5) of hopping conduction. Observed a crossover between these two mechanisms of hopping conduction. The scaling theory is applicable in the most temperature ranges of conduction mechanisms. and in the hopping conduction mechanisms as well. The obtained critical exponent for Mott (VRH) is equal to 3.6. For Efros-Shkolovskii (ES) percolation mechanism of conduction (PMC) the critical exponent is equal to 1.74. The Mandelbrot fractal systems formed in the present samples are temperature and compositional dependent. The Scanning electron microscope (SEM) result confirms the dependent the fractal figures formed in irradiated germanium on composition and irradiation fluency.