Collisional Carrier Excitation on GaAs (110)

We have extended our understanding of the coupling of gas-surface collisions to the electronic degrees of freedom of a solid. We have succeeded in measuring the collisional excitation of carriers by neutral atoms at the outermost atomic layer of GaAs (110) crystals despite the low carrier recombination lifetimes of GaAs (0.2-5 nsec). The experimental results show both similarities and some intriguing differences from our first measurements on InP surfaces. Because the GaAs (110) structure is well established, we are able to discuss our results in light of collision mechanisms elucidated in the realistic trajectory simulations on the scattering of Xe from GaAs (110) performed by Lim and Tully.