QUANTUM AND CLASSICAL RELAXATION-TIMES AND PROPERTIES OF A HETEROJUNCTION IN SELECTIVELY DOPED INP IN0.53GA0.47AS HETEROSTRUCTURES/

The following galvanomagnetic effects were determined at liquid-helium temperatures for a two-dimensional electron gas in InP/In0.53Ga0.47As heterostructures grown by the method of liquid phase epitaxy: the Hal l mobility; an oscillatory magnetoresistance in a quantum magnetic fie ld perpendicular to a heterojunction; a negative magnetoresistance in a weak magnetic field parallel to the two-dimensional layer. The quant um time, characteristic of damping of the Shubnikov-de Haas oscillatio ns due to collisional broadening of the magnetic subbands, was determi ned. The scattering mechanisms governing the transport time (tau) and the quantum time (tau(q)) were identified. The main mechanisms turned out to be the Coulomb scattering by charged centers for tau(q) and the scattering by heterojunction irregularities for tau. The average size of irregularities delta perpendicular to the heterojunction was found from an analysis of the negative magnetoresistance. Simultaneous solu tion of the equations for tau and tau(q) has made it possible to deter mine the two-dimensional density of charged defects N(z) and the avera ge period of irregularities A for each of the samples.