Effect of low nitrogen concentrations on the electronic properties ofInAs1−xNx

Abstract

We report cyclotron resonance ͑CR͒, transverse magnetoresistance ͑MR͒, and Hall effect studies of a series of n-type InAs 1−x N x epilayers grown on GaAs with x up to 1%. The well-resolved CR absorption lines, the classical linear MR, Shubnikov-de Haas magneto-oscillations, and negative MR revealed in our experiments provide a means of probing the effect of the N atoms on the electronic properties of this alloy system and reveal qualitative differences compared to the case of the wider gap III-N-V compounds, such as GaAs 1−x N x . In GaAs 1−x N x electron localization by N levels that are resonant with the extended band states of the host crystal act to degrade the electrical conductivity at small x ͑ϳ0.1%͒. These phenomena are significantly weaker in InAs 1−x N x due to the smaller energy gap and higher energy of the N levels relative to the conduction band minimum. In InAs 1−x N x the electrical conductivity retains the characteristic features of transport through extended states, with electron coherence lengths ͑l ϳ 100 nm at 2 K͒ and electron mobilities ͑ =6 ϫ 10 3 cm 2 V −1 s −1 at 300 K͒ that remain relatively large even at x =1%.

Linear magnetoresistance due to multiple-electron scattering by low-mobility islands in an inhomogeneous conductor

“…The transverse MR ratio defined as Δρ xx / ρ xx =[ ρ xx ( B z )− ρ xx (0)]/ ρ xx (0) was studied with magnetic fields, B z , up to 14 T, generated by a superconducting magnet, or in a pulsed solenoid at B z up to 47 T with a total pulse length of 100 ms. Figure 1a shows the B z -dependence of Δρ xx / ρ xx for an Hall-bar based on n -type InAs. A positive linear MR is observed at B z >1 T and is weakly affected by temperature in the range T =4.2–300 K. A weak oscillatory component of ρ xx is observed at low temperature ( T <20 K), which we attribute to the Shubnikov–de Haas effect in the two-dimensional electron gas that accumulates on the surface of InAs due to the bending of the conduction band by charged native surface defects12. The resistance of the surface two-dimensional electron gas at B z =0 T is at least one order of magnitude higher than ρ xx and, at all values of B z and T , the amplitude of the magneto-oscillations is much smaller than the measured monotonically increasing MR.…”

Systematic study of doping dependence on linear magnetoresistance in p-PbTe

“…For the sample with doping level of 0.02%, the LMR signal at 10 T is 10 X. R xy ¼ B=ðnedÞ % 40 X, so that dn is expected to be %25, which is nearly two orders of magnitude larger than the measured dn extracted from Hall measurements on different parts of the sample. Even though the PL model might explain the occurrence of LMR in materials such as Fe 1Àx Co x Sb 2 single crystals 27 and InAs 1Àx N x , 28 it fails to explain the data in case of the narrow-gap semiconductor PbTe.…”

Near band edge optical absorption and photoluminescence dynamics in bulk InAsN dilute-nitride materials

“…Development of InAsN bulk material with room temperature photoluminescence at wavelength up to 4.5 mm was reported in the year 2008 [12]. Optimized growth methodology improved the photoluminescence intensity and resulted into order of magnitude reduction of residual carrier concentration [13].…”

“…The close correspondence of the spectral location of the absorption edge and PL peak indicates marginal if any Moss-Burstein shift of absorption spectrum. Indeed, residual carrier concentration of the InAsN with 1% of nitrogen is expected to be only about 10 17 cm À 3[13], (although it was not directly measured in these samples). For this concentration of electrons (effective mass of about 0.05 of free electron mass[3]) the Fermi level is nearly at the conduction band edge.…”