Effect of initial surface reconstruction on the GaS/GaAs(001) interface

Abstract

We have used photoluminescence of a GaAs/Al0.3Ga0.7As near-surface quantum well structure to study the quality of the interface between GaAs and GaS deposited in ultrahigh vacuum (UHV) using [(tBu)GaS]4. In addition to the luminescence of the near-surface and the deep/reference quantum wells, luminescence was observed for the GaAs cap following the deposition of 100 Å of GaS. This additional feature demonstrates the high quality GaS/GaAs interface achievable through the UHV deposition of this precursor. The ratios of the integrated luminescence intensity of both the GaAs cap and the near-surface GaAs quantum well to the deep/reference quantum well indicate that there are fewer GaS/GaAs interface states for deposition on the Ga-rich GaAs(001)-(4×2)/(2×6) surface compared to deposition on the As-rich GaAs(001)-(2×4) surface. Furthermore, GaS passivated samples exposed to ambient conditions for eight months exhibit no luminescence degradation for the near-surface quantum well confirming that these films provide adequate passivation longevity.

Chemical Vapor Deposition of Gallium Sulfide Thin Films

“…Gallium sulfide is currently of interest as a surface passivation material for GaAs, − and alkaline earth thiogallates, such as cerium-doped Sr 2 Ga 2 S 5 , are promising materials for phosphor thin films in electroluminescent displays. − Chemists have contributed significantly to this area of research by synthesizing new molecular precursors to gallium sulfide and using the new precursors to prepare gallium sulfide films by chemical vapor deposition (CVD).…”

New value of old knowledge: sulphur-based GaAs surface passivation and potential GaAs application in molecular electronics and spintronics

“…Hasegawa et al [75] claimed that an increase in PLI was possible without decreasing the surface state by the negative charge created by the sulfide treatment on the GaAs surface. Experimental studies on S passivation show that the source of the surface states always decreases to a small or large extent after passivation treatment [92,103]. On this basis, the concept of Hasegawa et al [75] was found to be inconsistent with existing experimental results.…”

“…However, the As-S bonds were remarkably less stable and inferior in terms of their electrical properties. These facts prompted researchers to provide only Ga-S bonds on GaAs surfaces either by direct deposition [101][102][103] or by adding annealing treatment in addition to S passivation treatments [87].…”

“…Direct deposition of GaS was successfully performed using a gallium cluster ([(t-Bu) GaS] 4 ) as a singlesource precursor under ultra-high vacuum conditions of the MBE system [102,103,112]. The substrates were cleaned using trisodium ethylaminoarsinic (TDMAAS) and bisdimethylaminochloroarsinic (BDMAASCl) [102].…”