Magnetotransport and luminescence measurements in an n-type selectively doped InGaAs/GaAs strained quantum well structure

Abstract

A selectively doped, n‐type, single strained quantum well (SSQW) structure, consisting of an 8‐nm‐thick In_0.25Ga_0.75As layer sandwiched between thick GaAs layers, has been grown by molecular beam epitaxy. Low‐field Hall‐effect measurements from 4 to 300 K and field‐dependent magnetotransport measurements at 4 K show that conduction through the doped GaAs layers competes with conduction from the two‐dimensional electron gas confined by the InGaAs quantum well. Photoluminescence measurements at 4 K yield a band‐gap energy of 1.30 eV and confirm the transport measurement of carrier density in the InGaAs conducting channel. Analysis of the parallel‐conduction process yields channel carrier density and mobility which are consistent with data on strained‐layer superlattices (SLS’s) not exhibiting parallel conduction. Comparison of the SSQW and SLS results demonstrates that heavily doped SSQW structures require narrow doping spikes to avoid parasitic current paths.