Applied Science and Convergence Technology 1998; 7(4): 341-347
Published online November 1, 1998
Copyright © The Korean Vacuum Society.
Jung-Yeul Lee,In-Soo Kim,Jeonng-Sik Son,Dong-Lyeul Kim,In-Ho Bae,Dae-Nyoun Kim
We analyzed photoreflectance (PR) characterization of the Al_xGa_(1-x)As epilayer grown by molecular beam epitaxy (MBE) method. The band-gap energy (E。) satisfying low power Franz-Keldysh (LPFK) due to GaAs buffer layer is 1.415 eV, interface electrical field (E_i) is 1.05×10⁴V/㎝, carrier concentration (N) is 1.3×10^(15) ㎝-³. In PR spectrum intensity analysis at 300 K the A^* peak below E。 signal is low and distorted because of residual impurity in sample growth. The trap characteristic time (τ_i) of GaAs buffer layer is about 0.086 ㎳, and two superposed PR signal near 1.42 eV consist of the third derivative signal of chemically etched GaAs substrate and Franz-Keldysh oscillation (FKO) signal due to GaAs buffer layer.