  We investigate the dependence of the low-temperature photoluminescence
linewidths from InP-lattice-matched InGaAs/InAlAs quantum wells on the
low-angle misorientation from the (100) surface of the host InP substrate.
Quantum wells were grown on InP substrates misorientated by 0, 0.2, 0.4 and 0.6
degrees; 0.4 degrees was found to consistently result in the narrowest peaks,
with the optimal spectral purity of ~4.25 meV found from a 15nm quantum well.
The width of the emission from the 15nm quantum well was used to optimize the
growth parameters. Thick layers of Si-doped InGaAs were then grown and found to
have bulk, low temperature (77 K), electron mobilities up to \mu ~ 3.5 x 10^4
cm2/Vs with an electron concentration of ~1 x 10^16.
