Observation and control of the amphoteric behaviour of Si-doped InSb grown on GaAs by MBE

Abstract

The MBE growth and doping of heteroepitaxial layers of lnSb on GaAs (100) are investigated. The layers are assessed by low-field Hall and magnetoresistivity measurements and high-field Shubnikov-de Haas studies together with infrared transmission, and TEM. The mechanism for silicon incorporation is investigated as a function of growth temperature. At low growth temperatures =340 "C) silicon acts only as a donor and can produce electron concentrations up to 3 x 10l8 cm-3 with 77 K mobilities indentical to those found with bulk material. Although higher concentrations than 3 X 10l8 cm-3 can be achieved; auto-compensation appears to occur in those samples. The 77 K mobilities achieved for less heavily doped samples ( > 4 0 000 cm2 V-' S" for n = 1.2 x lo1' cm-3 for samples grown at 340 OC) are the highest lowtemperature mobilities yet reported for n-type lnSb films of = 1 p m thickness grown on GaAs. However, higher growth temperatures (-420 "C) combined with constant silicon flux are found to simultaneously decrease electron concentration and mobility measured at 77 K although the structural quality as assessed by TEM remains unchanged. Analysis of the observed behaviour in terms of the Brooks-Herring model of ionised impurity scattering, modified for non-parabolicity, suggests that silicon is acting amphoterically with compensation ratios (N,/N,) reaching 0.5 at the higher temperatures. The effect of the interface between GaAs and InSb (lattice mismatch = 14%) on the electrical properties is studied by introducing doping slabs of thickness =l300 8, at various distances (d) between the interface (d=O pm) and the surface (d-1.5 pm) of the epilayer. The mobility is degraded by more than a factor of two when the slab is located at the interface but deviations from the bulk mobility are small when the sample is grown at low temperatures and the slab is located more than =0.3 p m from the interface. Pronounced two-dimensional Shubnikov-de Haas effects are observed with the doping slabs. A series of peaks not periodic in reciprocal field (1/B) are found at low fields with B parallel to the slabs and are interpreted as arising from the diamagnetic depopulation of the large number of subbands occupied as a result of the considerable thickness of the slabs. Be doping at 2 x IO'' cm-3 was demonstrated and, as with silicon, the bulk mobility corresponding to this hole concentration was achieved.

Magnetically tunable non-reciprocal plasmons resonator based on graphene-coated nanowire

“…The electron density of doped InSb is N=2×10 24 m −3 , which has been previously demonstrated in mid-infrared metamaterials [27] and could be implemented using Si or Be as the dopant and molecular beam expitaxy (MBE) technology [28]. The effective mass m* is determined by m*=0.012me at a temperature T=300 K [29], in which the constant me is the electron rest mass.…”

Tuning the inherent magnetoresistance of InSb thin films

“…2 show that the optimal thickness, where the linearity ratio is at its maximum, is close to 1 m, above which the top layers are approaching bulk mobility values. 17,20 The model we put forward can certainly account for this result.…”

Review—Dopant Selection Considerations and Equilibrium Thermal Processing Limits for n+-In0.53Ga0.47As

“…[37][38][39][40][41][42][43] MBE experiments are perhaps the most convincing evidence that group IV dopants, and Si in particular, can be used as both a n and p-type dopants. [44][45][46][47][48] It is not clear if p-type doping in MBE growth from species which are nominally n-type via ion implantation or source diffusion remain p-type with subsequent thermal annealing. If a dopant was perfectly amphoteric it would be expected that no activation would result.…”