Sub-meV photoluminescence linewidth and > 10~6 cm~2/Vs electron mobility in AlGaAs/GaAs quantum wells grown by metalorganic vapor phase epitaxy on slightly misoriented substrates

摘要

We report sub-meV (as low as 0.6 meV) low-temperature photoluminescence linewidth and high low-temperature electron mobility (μ～ 1-1.5 X 10~6 cm~2/Vs) of GaAs quantum wells in AlGaAs barriers grown by standard metalorganic vapor phase epitaxy. These records values are achieved by epitaxial growth on (100) slightly misoriented substrates [ ≤ 0.6 degrees off-(100) GaAs substrates] in combination with a high Ⅴ/Ⅲ ratio for AlGaAs growth. Such small misorientations are sufficient to drastically modify the optical and transport properties as well as the growth mode and surface morphologies of both GaAs and AlGaAs epitaxial layers, allowing greater interface quality and reduced impurity incorporation. The quantum wells so obtained show optical properties comparable to high-quality samples grown by molecular beam epitaxy. In addition, the slight misorientation considerably reduces the impact of substrate temperature on electron mobility, which allows achieving high values of μ within a much broader range of growth temperatures.