DIRECT GROWTH OF ALGAAS GAAS SINGLE QUANTUM-WELLS ON GAAS SUBSTRATES CLEANED BY ELECTRON-CYCLOTRON-RESONANCE (ECR) HYDROGEN PLASMA/

Direct growth of AlGaAs/GaAs single quantum wells (SQWs) on GaAs subst rates without growing buff er layers is carried out by using electron cyclotron resonance (ECR) hydrogen plasma cleaning. SQW structures are successively grown by molecular beam expitaxy (MBE) after the cleanin g process without breaking the vacuum. Photoluminescence shows intense and narrow spectra, in clear contrast to that of conventional thermal cleaning. Atomic force microscopy (AFM) and secondary ion mass spectr oscopy (SIMS) analyses show that surface roughness and interface impur ity accumulations are significantly reduced as well. A flat and clean surface obtained by plasma cleaning improves the quality of grown laye rs.