Bulk gallium nitride

Bulk elastic modulus, of binary compound semiconductors, 22 145, 146-147t Bulk enzymes, from genetically engineered microbes, 22 480 Bulk erosion, 9 78 Bulk fluid velocity method, 16 688 Bulk gallium nitride, supercritical ammonia solution growth of, 14 96-97 Bulk gases... 

Blue lasers allow higher resolution, and hence higher density of optical storage of information, on devices such as DVDs than the infrared GaAs lasers allow. The earliest blue lasers were based on ZnSe but their lifetime proved too short for commercial applications. Lasers based on gallium nitride (GaN), first demonstrated in 1995, have proved to have greater lifetimes. In these lasers, the photons are produced not in a bulk semiconductor but in quantum wells. 

The five distinguishable second-order elastic moduli in a hexagonal crystal are Cn, Cn, Ci3, C33 and C44. There are reports of neither measured nor calculated values but, since each depends principally on the lattice constants [21] which vary by only about 10% across the nitrides, values for AIN (q.v.) may be used as a first approximation. The comparability of bulk moduli in indium, gallium and aluminium nitrides supports this approach. Estimates of the principal transverse and longitudinal elastic constants Ct and Ci are given in TABLE 2. 

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