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Abstract Tellurium‐hyperdoped silicon (Si:Te) shows significant promise as an intermediate band material candidate for highly efficient solar cells and photodetectors. Time‐resolved THz spectroscopy (TRTS) is used to study the excited carrier dynamics of Si hyperdoped with 0.5, 1, and 2%. The two photoexcitation wavelengths enable us to understand the temperature‐dependent carrier transport in the hyperdoped region in comparison with the Si region. Temperature significantly influences the magnitude of transient conductivity and decay time when photoexcited by light with a wavelength of 400 nm. Due to the differential mobilities in the Si and hyperdoped regions, such dependence is absent under 266‐nm excitation. Consistent with the literature, the charge‐carrier lifetime decreases with increasing dopant concentration. It is found that the photoconductivity becomes less temperature‐dependent as the dopant concentration increases. In the literature, the photodetection range of Si:Te extends to a wavelength of 5.0 µm at a temperature of 20 K. The simulation shows that carrier diffusion, driven by concentration gradients, is strongly temperature dependent and impacts transient photoconductivity decay curves. The simulation also revealed that, in the hyperdoped regions, the carrier recombination rate remains independent of temperature. 

Proton irradiation of both n-type and semi-insulating bulk samples of β-Ga2O3 leads to the formation of two paramagnetic defects with spin S = 1/2 and monoclinic point symmetry. Their high introduction rates indicate them to be primary irradiation induced defects. The first electron spin resonance (EPR1) has a g-tensor with principal values of gb = 2.0313, gc = 2.0079, and ga* = 2.0025 and quasi-isotropic superhyperfine interaction of 13G with two equivalent Ga neighbors. Under low temperature photoexcitation, this defect is quenched and replaced by a different metastable spin S = 1/2 center of comparable intensity. This second defect (EPR2) has similar principal g-values of gb = 2.0064, gc = 2.0464, and ga* = 2.0024 and shows equally superhyperfine interaction with two equivalent Ga atoms. This EPR2 defect is stable up to T = 100 K, whereas for T > 100 K the initial defect is recovered. Density functional theory calculations of the spin Hamiltonian parameters of various intrinsic defects are carried out using the gauge including projector augmented wave method in order to determine the microscopic structure of these defects. The intuitive models of undistorted gallium monovacancies or self-trapped hole centers are not compatible with neither of these two defects.