Spectral characterization of Mg2Si pn-junction diode depending on RTA periods

We have studied the effect of thermal annealing periods on the optoelectrical properties of Mg2Si pn-junction diodes fabricated by a conventional thermal diffusion process of Ag acceptor. The Au/Ag/n-Mg2Si (carrier concentration = 2 x 10(15) cm(-3), resistivity = 5-10 Omega cm) substrate was annealed at 550 degrees C in the Ar-atmosphere using a rapid thermal annealing (RTA) furnace. The annealing periods were varied between 2 and 10 minutes. Clear rectifying behavior of J-V characteristics was observed for the diodes annealed for more than 2 minutes. Spectral responsivity from the photon energy threshold of approximately 0.6 eV was demonstrated with the Mg2Si pn-junction diodes under the zero bias condition at room temperature. The maximum intensity of spectral responsivity was increased with decrease the annealing period. The spectral responsivity of the diode with the RTA periods of 4 minutes was approximately 4 times higher than that of 10 minutes annealed one. (c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim