The effect of arsenic on MBE-grown modulation-doped GaAs/AlGaAs heterostructures

• Main Authors: Patricio, Michelee G., Estacio, Elmer, Somintac, Armando, Podpod, Arnita, Dorilas, Raphael B., Salvador, Arnel A.
• Format: text
• Published: Animo Repository 2002
• Subjects: Gallium arsenide; Heterostructures; Physics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/5504
• Institution: De La Salle University

In this paper, the effect of As on the mobility and junction electric field of modulation-doped GaAs/AlGaAs heterostructures were investigated by varying the As flux during the MBE growth of the samples. Hall measurements using the van der Pauw configuration determined the carrier concentration and Hall mobility. The carrier concentration was observed to increase with As flux. The room temperature mobilities of the samples tend to decrease, while the 77 K mobilities increase with increasing As flux. Photoreflectance spectroscopy was utilized to derive the junction electric field. These values were observed to be higher than the electric field values calculated from Hall measurements for the samples grown at relatively lower As fluxes. This may be the effect of electron traps due to As vacancies coupled to C impurities. A remarkable improvement in the 77 K mobility of the sample grown after baking the substrate holder was observed. The 10 K mobility however was low compared to the benchmark set by other groups.