A photoluminescence and Hall-effect study of GaSb grown by molecular-beam epitaxy

Abstract

Unintentionally doped gallium antimonide has been grown by molecular-beam epitaxy on gallium arsenide and gallium antimonide. Substrate temperatures in the range 480 to 620 °C and antimony to gallium flux ratios from 0.65 : 1 to 6.5 : 1 have been investigated. The deposition conditions have been related to growth morphology and to the electrical and optical properties of the epitaxial films. A strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material in terms of both optical and electrical properties was obtained with the minimum antimony stable growth at a particular substrate temperature. All the material exhibited residual p-type behavior. The lowest hole concentration achieved was 7.8×1015 cm−3 with a corresponding room-temperature mobility of 950 cm2/V s. The narrowest PL (photoluminescence) features observed were peaks associated with bound exciton transitions with half-widths of 2–3 meV.

Electrical properties of n-type GaSb substrates and p-type GaSb buffer layers for InAs/InGaSb superlattice infrared detectors

“…Ivanov et al 20 and Johnson et al 21 are representative of what has been reported for epitaxial GaSb on semi-insulating GaAs substrates. Ivanov et al reported 77 K hole concentrations and mobilities of 1.1x10 16 to 1.5x10 16 cm −3 and 2700 to 4580 cm 2 /Vs while Johnson et al reported 1.5x10 15 to 8x10 15 cm −3 and 756 to 310 cm 2 /Vs at that temperature, to which our values in Table II, 1x10 15 to 2x10 16 cm −3 and 3000 to 7000 cm 2 /Vs, compare favorably.…”

“…2 are in areal units (cm −2 ) because that is the output of the multicarrier analysis. Converting the 300 K concentrations to volumetric units we get 1.23x10 16 cm −3 for the G band and 6.28x10 16 cm −3 for the L band. The total free electron concentration is the sum of these two concentrations, 7.51x10 16 cm −3 .…”

“…Thus attempts were made to develop lightly doped n-type GaSb (n-GaSb) where interband absorption is not an issue at low temperatures due to the 80 meV separation of the G and L conduction bands. GaSb wafers with room temperature concentrations as low as 2x10 16 cm −3 have recently become available with significantly reduced infrared absorption 6 enabling backside illumination. Allen et al 6 reported controlling the growth to reduce the concentration of intrinsic acceptor defects such as the gallium antisite which has been shown to be the principal acceptor in undoped GaSb.…”

Epitaxial growth of GaSb and InAs fins on 300 mm Si (001) by aspect ratio trapping

“…GaAs (001) is a relatively usual substrate to grow high crystal quality blanket GaSb films by MBE [22][23][24]. Under appropriate growth conditions, the strain energy associated with the 7.8% lattice mismatch is relaxed through the formation of a periodic array of 90° Lomer misfit dislocations at the GaSb/GaAs [001] interface, which largely hinders the formation of threading dislocations.…”

Low-temperature growth of GaSb epilayers on GaAs (001) by molecular beam epitaxy

“…Y. Li et al [18] reported on 1.63×10 16 cm -3 room temperature hole concentration at growth temperature of 490°C, while M. Lee et al [25] had 7.8×10 15 cm -3 at growth temperature 550°C. A growth rate of 1 μm/h was used by the two previous groups.…”