TY - JOUR
T1 - Photoconductivity and electroreflectance study of cubic GaN/GaAs(001) heterostructures by optical-biasing technique
AU - Katayama, Ryuji
AU - Kuroda, M.
AU - Onabe, K.
AU - Shiraki, Y.
PY - 2002/12/1
Y1 - 2002/12/1
N2 - Photoconductivity (PC) and electroreflectance (ER) spectrum measurements were carried out for the cubic GaN/GaAs and cubic AlGaN/GaN/GaAs heterostructures grown by LP-MOVPE. Both spectra contained significantly overlapped signals from the c-(Al)GaN epitaxial layer and the underlying GaAs layer, but the latter was successfully suppressed and distinguished from the former by the use of an additional steady-state illumination of Ar+ laser as an optical bias. The temperature dependence of the optically-biased PC spectrum showed that there remained structural disorder in the c-GaN layer indicated by the temperature-independent Urbach energy. From the temperature dependence of the ER spectrum, the E0 critical point of c-GaN observed likely corresponds not to excitonic transition but to free-carrier transition as it shifted by ∼30 meV to higher energies than the reported value, probably due to the dissociation of exciton by the relatively large modulation field applied to the c-(Al)GaN layer.
AB - Photoconductivity (PC) and electroreflectance (ER) spectrum measurements were carried out for the cubic GaN/GaAs and cubic AlGaN/GaN/GaAs heterostructures grown by LP-MOVPE. Both spectra contained significantly overlapped signals from the c-(Al)GaN epitaxial layer and the underlying GaAs layer, but the latter was successfully suppressed and distinguished from the former by the use of an additional steady-state illumination of Ar+ laser as an optical bias. The temperature dependence of the optically-biased PC spectrum showed that there remained structural disorder in the c-GaN layer indicated by the temperature-independent Urbach energy. From the temperature dependence of the ER spectrum, the E0 critical point of c-GaN observed likely corresponds not to excitonic transition but to free-carrier transition as it shifted by ∼30 meV to higher energies than the reported value, probably due to the dissociation of exciton by the relatively large modulation field applied to the c-(Al)GaN layer.
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U2 - 10.1002/1521-3951(200212)234:3<877::AID-PSSB877>3.0.CO;2-H
DO - 10.1002/1521-3951(200212)234:3<877::AID-PSSB877>3.0.CO;2-H
M3 - Article
AN - SCOPUS:0036928773
VL - 234
SP - 877
EP - 881
JO - Physica Status Solidi (B): Basic Research
JF - Physica Status Solidi (B): Basic Research
SN - 0370-1972
IS - 3
ER -