MBE growth of novel GaAs/n-AlGaAs field-effect transistor structures with embedded InAs quantum traps and their transport characteristics

Novel GaAs/n-AlGaAs FETs structures have been grown by molecular beam epitaxy (MBE) by placing InAs quantum dots near the channel. We show that the threshold voltage can be shifted by the trapping or detrapping of electrons in these dots. The number of electrons trapped by each InAs dot is estimated to be one or two, representing the finiteness of quasi-stable trap states. The concentration of trapped electrons at 4.2 K is identical to that at 77 K, suggesting that trapped electrons stay in the ground level up to relatively high temperatures.