DETERMINATION OF THE X-CONDUCTION-SUBBAND ENERGIES IN TYPE-II GAAS ALAS/GAAS QUANTUM-WELL BY DEEP-LEVEL TRANSIENT SPECTROSCOPY/

Using deep level transient spectroscopy (DLTS) the X conduction-subban d energy levels in an AlAs well sandwiched by double GaAs layers were determined. Calculation gives eight subbands in the well with well wid th of 50 Angstrom. Among them, five levels and the other three remaind ers are determined by using the large longitudinal electron effective mass m(1)(1.1m(0)) and transverse electron effective mass m(t)(0.19m(0 )) at X valley, respectively. Two subbands with the height energies we re hardly detectable and the other six ones with lower energies are ac tive in the present DLTS study. Because these six subbands are close t o each other, we divided them into three groups. Experimentally, we ob served three signals induced from the three groups. A good agreement b etween the calculation and experiment was obtained. (C) 1995 American Institute of Physics.