Defect study of molecular beam epitaxy grown undoped GalnNAsSb thin film using junction-capacitance spectroscopy

摘要

Defects in undoped GalnNAsSb thin film (i-GalnNAsSb) were investigated by junction-capacitance technique using admittance and transient photocapacitance (TPC) spectroscopy. An electron trap D2 was identified at 0.34 eV below the conduction band (E_C) of i-GalnNAsSb using admittance spectroscopy. Optical transition of valance band (E_v) electrons to a localized state OH1 (E_v + 0.75 eV) was manifested in negative TPC signal. Combined activation energy of OH1 and D2 defect corresponds to the band-gap of i-GalnNAsSb, suggesting that OH1/D2 acts as an efficient recombination center. TPC signal at ～1.59eV above E_v was attributed to the nitrogen-induced localized state in GalnNAsSb.