INPLANE EFFECTIVE-MASS IN NARROW QUANTUM-WELLS OF NONPARABOLIC SEMICONDUCTORS

A formula is derived for the in-plane effective mass in narrow quantum wells, taking into account the effects of energy band nonparabolicity . The variation of the mass with the width of the well is studied by u sing the formula for four systems of wells. The mass is nearly the sam e as the velocity effective mass of the bulk material of the well in G aAs/Ga0.7Al0.3As wells. It is about 8% larger in InAs/InP wells, but i s significantly larger in very narrow wells of Ga0.47In0.53As/InP syst ems. In the case of InAs/Ga0.58Al0.42Sb wells, the in-plane mass diffe rs from the well mass by large amounts for all well widths of interest .