Direct Viewing of Imperfections in Germanium p-n Junction

Abstract

A p-n junction was made by alloying indium on an n-type germanium pellet and it was put into an electrolyte solution of copper salt. When suitable reverse voltage was applied on the junction by a charged condenser, copper shaded pattern was deposited on the opposite side of the alloyed surface in accordance with the density of the reverse current flowing through every part of the p-n junction. By this method, the breakdown at the imperfections of p-n junction due to the defects in the germanium crystal, those at the periphery of p-type recrystallized layer, and those inside p-n junction grown in alloying process were observed. Then, the cross section was made referring to the pattern, and several kinds of the imperfections of p-n junction were observed under microscope.