Low-angle misorientation dependence of the optical properties of InGaAs/InAlAs quantum wells

TL;DR

This study examines how low-angle misorientation of InP substrates affects the optical quality of InGaAs/InAlAs quantum wells, identifying optimal growth conditions for narrow photoluminescence linewidths and high electron mobility.

Contribution

It demonstrates that a 0.4-degree misorientation yields the narrowest photoluminescence peaks and optimizes growth parameters for high-quality quantum wells.

Findings

0.4-degree misorientation produces the narrowest PL linewidths (~4.25 meV)

Optimized quantum wells exhibit electron mobilities up to 3.5 x 10^4 cm²/Vs at 77 K

Growth parameters were refined based on emission linewidth measurements

Abstract

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.