Properties of the two-dimensional electron gas in modulation-doped GaInAs(P)/InP structures grown by low-pressure metalorganic vapor-phase epitaxy

Abstract

This paper is concerned with the characteristics of the two-dimensional electron gas (2DEG) at modulation-doped GaInAs/InP and GaInAsP/InP heterojunctions and GaInAs/InP single-quantum-well structures grown by low-pressure metalorganic vapor-phase epitaxy (LP-MOVPE) at 20 hPa. Using trimethyl-In, trimethyl-Ga, AsH3, and PH3 as source materials, this process permits the deposition of very uniform films with abrupt interfaces and doping profiles. We give the first detailed analysis of modulation-doped structures by classical Hall effect, Shubnikov–de Haas, and quantum Hall-effect measurements. Study of the scattering mechanisms of the 2DEG in modulation-doped GaInAs/InP and GaInAsP/InP structures reveals a small interface roughness and a low impurity content at the interfaces. Electron mobilities at 4.2 K up to 189 000 cm2/V s for a GaInAs/InP and 72 000 cm2/V s for a GaInAsP/InP heterojunction as well as values as high as 170 000 cm2/V s for a GaInAs/InP quantum well structure demonstrate the excellent control of the growth process and the quality of the material attainable by LP-MOVPE.