A thermophotovoltaic cell is provided containing strained or
lattice-matched quantum wells that have a bandgap smaller than the
bandgap of the InGaAs alloy. The alloy is lattice-matched to the
substrate. These narrow bandgap quantum wells provide more efficient
conversion of IR emission from a black body or other emitter by
converting energy from a wider range of wavelengths than a conventional
single junction cell. The thickness of the quantum well region and the
individual thickness of the individual quantum wells are chosen to avoid
lattice mismatch defects which cause degradation of thick conventional
lattice mismatched devices.
