Electronic properties of [formula omitted] strained-layer superlattices prepared by hydride vapor phase epitaxy

Abstract

InAs x P 1− x InAs superlattices with 0.63 ≤ × ≤ 0.83 have been grown by hydride vapor phase epitaxy on semi-insulating Fe-doped InP(100) substrates using a single barrel horizontal reactor. The superlattices consisted of 60–150 layers of alternate InAsP and InAs with an individual layer thickness in the range of 200–500 Å. The net carrier concentrations for these structures at 295 K are in the low 10 16 cm −3 range with electron mobilities between 8,130 and 12,100 cm 2/(V − sec.). The highest electron mobility was obtained for an InAs 0.7 P 0.3 InAs superlattice, which has a lattice misfit strain of 0.95%. The highest 77 K mobility observed for the InAsP/InAs structures was 4.7 × 10 4 cm 2/V − sec.) for a net carrier concentration of 1.15 × 10 16 cm −3. Electronic conduction mechanisms in the superlattices were studied from their magnetotransport properties at 1.6 K. Highly anisotropic magnetoresistance was noted for magnetic fields perpendicular and parallel to the layers. For low fields a negative magnetoresistance that was proportional to the square of the magnetic field was observed. For samples with high electron mobility, oscillations in the magnetoresistance were noted at high magnetic fields.