TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The structure further comprises at least one additional metal migration semiconductor barrier layer embedded within the semiconductor contact layer. The metal migration semiconductor barrier layer is aluminum gallium arsenide, gallium indium phosphide, gallium indium arsenide, strain-balanced superlattices, strained layers, or lattice-matched materials. It is made of aluminum indium phosphide having a thickness of 250-500 Angstrom. The semiconductor active region includes a first set of semiconductor active layers (81) based on gallium arsenide and a second set of semiconductor active layers (82) based on gallium indium phosphide. The first set of active layers has a thickness of 2-4 microns, and the second set of active layers has a thickness of 0.5-1.0 microns. The semiconductor contact layer is gallium arsenide. It includes a first region (83) of gallium arsenide having a thickness of 1000-5000 Angstrom and a doping of 1-5x1018/cm3; a second region (84) of gallium arsenide having a thickness of 1000-5000 Angstrom and a doping of 1-5x1018/cm3; and a third region (85) of gallium arsenide having a thickness of approximately 0-2000 Angstrom and a doping of 1-5x1019/cm3. The metal contact is a titanium/gold/silver metallization, or titanium/platinum/silver metallization. The metal contact includes a titanium layer (86) having a thickness of 25-100 Angstrom, where the titanium layer is deposited on the third region of the semiconductor contact layer; gold layer (87) having a thickness of 300-600 Angstrom and being deposited on the titanium layer; and silver layer (88) having a thickness of 40000-60000 Angstrom and being deposited on the gold layer. The substrate has a thickness of 100-300 microns. It is an elemental semiconductor, or a III-V compound semiconductor.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The structure further comprises at least one additional metal migration semiconductor barrier layer embedded within the semiconductor contact layer. The metal migration semiconductor barrier layer is aluminum gallium arsenide, gallium indium phosphide, gallium indium arsenide, strain-balanced superlattices, strained layers, or lattice-matched materials. It is made of aluminum indium phosphide having a thickness of 250-500 Angstrom. The semiconductor active region includes a first set of semiconductor active layers (81) based on gallium arsenide and a second set of semiconductor active layers (82) based on gallium indium phosphide. The first set of active layers has a thickness of 2-4 microns, and the second set of active layers has a thickness of 0.5-1.0 microns. The semiconductor contact layer is gallium arsenide. It includes a first region (83) of gallium arsenide having a thickness of 1000-5000 Angstrom and a doping of 1-5x1018/cm3; a second region (84) of gallium arsenide having a thickness of 1000-5000 Angstrom and a doping of 1-5x1018/cm3; and a third region (85) of gallium arsenide having a thickness of approximately 0-2000 Angstrom and a doping of 1-5x1019/cm3. The metal contact is a titanium/gold/silver metallization, or titanium/platinum/silver metallization. The metal contact includes a titanium layer (86) having a thickness of 25-100 Angstrom, where the titanium layer is deposited on the third region of the semiconductor contact layer; gold layer (87) having a thickness of 300-600 Angstrom and being deposited on the titanium layer; and silver layer (88) having a thickness of 40000-60000 Angstrom and being deposited on the gold layer. The substrate has a thickness of 100-300 microns. It is an elemental semiconductor, or a III-V compound semiconductor.