Electrical properties and ultrafast photo-response of InGaAs/InP grown by low-temperature molecular beam epitaxy with a GaAs decomposition source

摘要

Lattice-matched InGaAs on (1 00) InP was grown by molecular beam epitaxy with arsenic dimers (As_2) at a growth temperature (T_g) range of 250-470℃. Measurements of double-crystal X-ray diffraction reveal that Δa_(⊥)/a_o of low-temperature-grown (LTG) InGaAs increases from 0.82 x 10~(-2) (T_g= 470℃) to 4.1 x 10~(-2) (T_g= 250℃) as T_g decreases. The measurements also indicate that excess arsenics are easily incorporated as antisites. All grown samples show a clear crystalline structure and are strong n-type. When T_g is decreased from 470℃ to 250℃, then according to the Hall measurement the carrier concentration increases from 5.0 x 10~(-16) to 2.4 x 10~(-18) cm~(-3) and according to the time-resolved reflectivity measurement the carrier lifetime decreases from 14.02 to 2.33 ps. Finally, for InGaAs/InP grown at 250℃, the incorporation of Be decreases the carrier lifetime to 1.86 ps and the residual n-type carrier concentration to 5.0 x 10~(-16) cm~(-3). Crystallized InGaAs/InP with LTG material properties was obtained with a smaller Ⅴ/Ⅲ ratio and at higher growth temperature, compared to those with As_4.