Electrical Resistivity of Undoped GaAs Single Crystals Grown by Magnetic Field Applied LEC Technique

Abstract
We have grown undoped GaAs single crystals by magnetic field applied LEC (MLEC) technique and measured their electrical and optical properties. The most striking result was that the electrical resistivity of undoped GaAs changed from being semi-insulating (108 ohm-cm) to semi-conducting (10 ohm-cm) by increasing the magnetic field (0 to 1300 Oe). PL, DLTS and SIMS measurements suggest that the decrease of resistivity is mainly due to the decrease in concentration of the deep level defects.