Detailed analysis of carrier transport in InAs0.3Sb0.7 layers grown on GaAs substrates by metalorganic chemical-vapor deposition

Abstract

InAs0.3Sb0.7 layers with mirrorlike morphology have been grown on GaAs substrates by low-pressure metalorganic chemical vapor deposition. A room-temperature electron Hall mobility of 2×104 cm2/V s has been obtained for a 2-μm-thick layer. Low-temperature resistivity of the layers depended on TMIn flow rate and layer thickness. Hall mobility decreased monotonically with decreasing temperature below 300 K. A 77 K conductivity profile has shown an anomalous increase in the sample conductivity with decreasing thickness except in the near vicinity of the heterointerface. In order to interpret the experimental data, the effects of different scattering mechanisms on carrier mobility have been calculated, and the influences of the lattice mismatch and surface conduction on the Hall measurements have been investigated by applying a three-layer Hall-effect model. Experimental and theoretical results suggest that the combined effects of the dislocations generated by the large lattice mismatch and strong surface inversion may lead to deceptive Hall measurements by reflecting typical n-type behavior for a p-type sample, and the measured carrier concentration may considerably be affected by the surface conduction up to near room temperature. A quantitative analysis of dislocation scattering has shown significant degradation in electron mobility for dislocation densities above 107 cm−2. The effects of dislocation scattering on hole mobility have been found to be less severe. It has also been observed that there is a critical epilayer thickness (∼1 μm) below which the surface electron mobility is limited by dislocation scattering.

Magnetron sputtering growth of InAs0.3Sb0.7 films on (100) GaAs substrates: Strong effect of growth conditions on film structure

“…The data in Table 2 show that sample F exhibits better quality than sample D, suggesting that growth conditions still have a pronounced influence on material quality even though the epitaxial conditions are already met. The Hall mobilities of the samples are all relatively low compared with those grown by MBE [8,10] and MOCVD [12]. Considering the high carrier concentrations (410 18 cm À3 ) in the samples, it should be mainly attributed to the impurities unintentionally but heavily doped to the InAs 0.3 Sb 0.7 films.…”

“…It can be inferred that the threshold value of growth rate lies on the diffusion speed of the atoms absorbed on the substrate surface. Note that by MBE [8,10] or MOCVD [2,12] can be achieved at the substrate temperature range of 400-480 1C, and one could see some differences in growth mechanism between magnetron sputtering and MBE or MOCVD. Fig.…”

“…So far, epitaxial films of mid-range InAs x Sb 1Àx have been successfully grown on GaAs substrates by molecular beam epitaxy (MBE) [8][9][10][11] and MOCVD [2,12,13]. However, hitherto no report in the literature about the growth of InAs x Sb 1Àx films on GaAs substrates by magnetron sputtering has been found.…”

Electrical characterization of thin InAs films grown on patterned W∕GaAs substrates

“…Studies of strained InAs grown on GaAs and Si substrates [10][11][12][13][14] have shown that the deposited layer may be separated into three regions: the interface, the bulk, and the surface. The extent of the interface layer varies with different growth conditions and especially with various attempts to reduce the dislocation density where it can be reduced from 1 m ͑Ref.…”

Anomalous Behavior of the Hall Effect in III-V Heterostructures

“…The effect of dislocations on the electrical conduction in GaAs-based compounds has been widely investigated [2][3][4][5][6][7][8][9][10][11][12]. However, skew scattering has not been taken into account.…”