Double modulation-doped AlGaAs/InGaAs heterostructure with a graded composition in the quantum well

Abstract
A new double modulation‐doped AlGaAs/InGaAs heterostructure with a graded composition in the InGaAs quantum well (QW) has been designed and electrically characterized. An InGaAs QW with a rectangular‐like potential profile in the presence of the two dimensional electron gas is obtained by a two‐step grading of the In composition, which results in a broad and symmetric electron distribution profile even under various voltages. The Hall measurement shows a very high electron mobility of 7230 cm2/V s and an electron sheet density of 4.1×1012/cm2 at room temperature. To our knowledge, this is the highest mobility ever reported so far for the double modulation‐doped Al0.3Ga0.7As/In0.2Ga0.8As field‐effect transistor structure.