A semiconductor device includes a first III-V nitride-based layer, a second III-V nitride-based layer, a nitride-based transition layer, and a nitride-based transistor. The first III-V nitride-based layer is disposed over a substrate by applying a first V/III ratio in a first range. The second III-V nitride-based layer is disposed over the first III-V nitride-based layer by applying a second V/III ratio in a second range, in which the first range and the second range are mutually exclusive. The nitride-based transition layer is disposed between the first III-V nitride-based layer and the second III-V nitride-based layer to connect the first III-V nitride-based layer with the second III-V nitride-based layer, in which the nitride-based transition layer is formed by applying a third V/III ratio in a third range between the first range and second range. The nitride-based transistor is disposed over the second III-V nitride-based layer.

The present invention provides a semiconductor structure comprising: a silicon substrate in [100] orientation; a scandium oxide layer over the substrate, in [111] orientation; and a scandium-rare earth-oxide layer over the scandium oxide layer. The scandium-rare earth-oxide layer can have a graded composition to transition lattice constant to match to a subsequent layer, such as an indium nitride layer having very high electron drift velocity. InN over Si (100) offers transistors, photonics and passive electronics that operate in the terahertz frequency range.

Solar cell structures comprising a plurality of solar cells, wherein each solar cell is separated from adjacent solar cell via a tunnel junction and/or a resonant tunneling structure (RTS), are described. Solar cells are implemented on Ge, Si, GaN, sapphire, and glass substrates. Each of the plurality of solar cells is at least partially constructed from a cell material which harnesses photons having energies in a predetermined energy range. In one embodiment each solar cell comprises of at least two sub-cells. It also describes a nano-patterned region/layer to implement high efficiency tandem/multi-junction solar cells that reduces dislocation density due to mismatch in lattice constants in the case of single crystalline and/or polycrystalline solar cells. Finally, solar structure could be used as light-emitting diodes when biased in forward biasing mode. The mode of operation could be determined by a programmed microprocessor.

A semiconductor laminate at least including: a base; a buffer layer; and a crystalline metal oxide semiconductor film containing at least one metal element and having a corundum structure, the semiconductor laminate having the buffer layer on a main surface of the base directly or via another layer, the semiconductor laminate having the crystalline metal oxide semiconductor film on the buffer layer. The buffer layer is a laminate structure of a plurality of buffer films each with a different composition, and at least two buffer films of the plurality of buffer films have a film thickness of 200 nm or more and 650 nm or less.