Space-charge controlled conduction in low-temperature-grown molecular-beam epitaxial GaAs,

peer reviewedCurrent transport in low-temperature (LT) molecular-beam epitaxial GaAs grown at 200-300 °C on an n+ GaAs substrate is studied by means of current–voltage–temperature characteristics. The resistivity of LT GaAs at low electric fields is rho>108 Ohm cm, much higher than resulting from van der Pauw measurements. It is found that the measured resistivity decreases with increasing the LT GaAs thickness. This is explained by space-charge effect in the vicinity of n+/LT GaAs junction and subsequent suppression of hopping conduction in the high-field junction region