Etching behavior of microdefect in diluted magnetic semiconductor Hg_0.89Mn_0.11Te

The surface of Hg_0.89Mn_0.11Te wafer grown by vertical Bridgman method after being etched 30, 60, 90, 120, and 150 s by etchant of 150 mL saturation water solution of potassium bichromate and 20 mL HCl have been observed by optical microscope and scanning electron microscope. Grain boundaries and Te inclusions are distinctly observable after etched 30 s, but the intrinsical dislocation of wafer is only observable after 120 s. The density of dislocation etch pits shows a peak value at 60 s with increasing etching time, and turns to a steady state value after 120 s. The dimensions of etch pits is always increase with etching time increasing. The analysis shows that the initial dislocation etch pits are induced by the surface damaged layer.