Published online by Cambridge University Press: 15 February 2011
LT GaAs(220°C) was grown on an n+ substrate and capped with n+ GaAs grown at 600°C (n-i-n). Complete IV and CV measurements were performed. The IV characteristics exhibit ohmic, trap-filling and space-charge-limited regimes. We have developed a model based upon the compensation of background shallow acceptors by deep donor traps, large concentrations of which have been shown to exist in LT GaAs. Computer simulation of the IV curve is compared with experimental results. The “breakdown” is attributed to trapfilling under electron injection. It is also found that when the voltage across the structure is changed, the current takes several seconds to reach steady state. This is consistent with our model, which assumes slow trapping and detrapping in the LT GaAs. High frequency CV measurements show the capacitance to be fairly constant for voltages below “breakdown”.