Pressure and Temperature Dependences of Selected Semiconductor Minimum Energy Gaps

Si and GaAs data from Sze (1981). [6] Remaining data from the CRC Handbook of Chemieal Physics, 2001. [3] When no value is given it may be assumed that B 300K. 

Theoretically, the opposite dependence of direct and indirect gaps on pressure could be used to convert indirect gap materials to direct gaps. However, a negative pressure (tensile stress) would have to be applied to achieve this conversion. Ceramics, including semiconductors, tend to be weaker in tension than in compression. Even by placing the indirect material in a strained-layer superlattice (see Chapter 7), which can achieve the highest tensile stress levels, it has been impossible to convert indirect semiconductors to direct gaps before the stress is relieved by formation of dislocations or by fracture. 

Homopolar semiconductors consist of a single type of atoms. 

Molecular orbitals are linear combinations of atomic orbitals. 

Symmetric combinations of atomic or molecular orbitals produce bonding states Antisymmetric combinations produce antibonding states. 

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Table 5.4 Pressure and Temperature Dependences of Selected Semiconductor Minimum Energy Gaps...

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