Camel’s back structure

The existence of the camel s back structure and of the already mentioned relative minimum of the CB at the X3 point, introduces complexity in the determination of the values of the electron effective masses for the interpretation of experimental data [51]. The energy dispersion at the camel s back for GaP and AlSb are described by the expression ... 

Table 3.5. CB parameters of three cubic crystals with camel s back structure near the CB minimum Xi at the X point of the BZ. The values for GaAs apply under hydrostatic pressure above 4 GPa. The effective masses are in me units...

The critical 3p i-2p i spacing is expected to be independent of the nature of the chemical donor, but it differs significantly between Sica and Op. This reflects the fact that the CB minimum for the donors on P site is associated with the Xi camel s back structure. Variational calculations based on k.p perturbation theory have been performed for P-site donor and compared self-consistently with spectroscopic data [40]. The calculations are performed as a function of the ratio of a non-parabolicity parameter9 Q to the separation A between CBs Xi and X3. The authors use an anisotropy parameter p equal... 

Table 6.40. Calculated energy levels (meV) for donors in GaP. The first row is for the donor on P site (S, Se, Te) associated with the CB with the camel s back structure...

Aluminium Phosphide (AlP). Aluminium phosphide is an indirect, wide-gap semiconductor. The minima of the conduction bands are located at the X point of the Bril-louin zone. The top of the valence band has the structure common to all zinc blende semiconductors (Fig. 4.1-67). Aluminium Arsenide (AlAs). Aluminium arsenide is a wide-gap semiconductor with a band structure (Fig. 4.1-68) similar to that of AlP. Measurements have revealed a camel s back structure near X. 

Effective masses at X, neglecting camel s back structure. Effective masses at L. 

Gallium Phosphide (GaP). Gallium phosphide is an indirect-gap semiconductor. The lowest set of conduction bands shows a camel s back structure the hand minima are located on the A axes near the zone boundary. The valence hands show the usual stracture characteristic of zinc blende semiconductors. 

Indium Phosphide (InP). Indium phosphide is a direct-gap semiconductor. The conduction band minimum is situated at F. Higher conduction band minima at L and X have been detected in optical experiments. The X-band minima show no camel s back structure, in contrast to most other III-V compounds with the zinc blende structure. The valence band has the structure common to all zinc blende-type semiconductors (Fig. 4.1-113). 

---