Extraction of interface states at emitter-base heterojunctions in AlGaAs/GaAs heterostructure bipolar transistors using sub-bandgap photonic excitation. - Se Woon Kim; Kang Seob Roh; Seung Hwan Seo; Kwan Young Kim; Gu Cheol Kang; Sunyeong Lee; Chang Min Choi; So Ra Park; Jun Hyun Park; Ki Chan Chun; Kwan Jae Song; Dae Hwan Kim; et al. (Microelectron. Reliab., 2008)