Since the lattice constant of GaSb is fairly large, GaSb is a promising material for mixed III-V compounds whose band gaps correspond to wavelengths longer than 1.5 ?m.1 This is important since transmission loss due to Rayleigh scattering is significantly low at these wavelengths.2
Quaternary GalnAsSb and GaAlAsSb epitaxial layers on GaSb substrates1 , 3 , 4 are promising for LEDs and lasers in the range of 2-2.3 ?m 5 7 as are AlGaSb photodetectors8 , 9 at wavelengths longer than 1.5 ?m. InAs/GaSb superlattices are promising for ultrahigh speed electronic devices.10 InGaSb Gunn oscillators have also been studied.11 A recent attractive application of GaSb is for infrared solar cells combined with GaAs based solar cells and for thermophotovoltaic cells in order to convert wasted thermal energies to electric energies.12
The physical properties of GaSb have been investigated and they are reported in various references.13 , 14 Typical data are shown in Table 9.1.
| Crystal Structure | zincblende |
|---|---|
| Lattice Constant | 6.094 |
| Density | 5.613 g/cm 3 |
| Melting Point | 712 C |
| Linear Expansion Coefficient | 6.7 10 -6/deg |
| Thermal Conductivity | 0.33 W/cm K |
| Dielectric Constant | 15.69 |
| Refractive index | 3.82 |
| Bandgap at Room Temperature | 0.70 eV |
| Intrinsic Carrier Concentration | 10 14 cm -3 |
| Electron Mobility | 7,700 cm 2/V sec |
| Hole Mobility | 1,400 cm 2/V sec |
GaSb has a direct band gap of 0.72 eV at room temperature and a cubic lattice constant of 6.095 which permits the...
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