Photoemission oscillations observed in chemical beam epitaxy of GaAs using triethylgallium and organoarsines

摘要

Near-threshold photoemission (TPE) analysis is a promising diagnostic tool for vapor deposition processes operating under low pressure. The technique is very sensitive to surface phenomena such as gas-solid interactions, surface reactions and growth modes because the work function strongly depends on these events. TPE has been used successfully for in situ monitoring of GaAs epitaxial growth using metalorganic precursors for both Ga and As sources. The photocurrent intensity oscillates in the early stages of 2D growth with a period corresponding to the formation of a monolayer. This oscillatory behavior has been observed for the first time using the organometallic systems GaEt_3/AsEt_2H/H_2 and GaEt_3/As~tBuH_2 despite a complex surface chemistry.