Effect of Thermal Annealing on Band Edge Absorption Spectrum of Arsenic-Ion-Implanted GaAs

We report the effect of annealing temperature on the near bandgap transmittance, absorption coefficient, as well as the evolution of shallow-level defects of arsenic-ion-implanted GaAs (referred as GaAs:As+) by using Fourier transform infrared spectroscopy. By either fitting the absorption curve with A(hv-Eg)1/2 or extrapolating the ((alpha) hv)2 curve to the abscissa, the blue shift of bandgap energy of RTA-annealed GaAs:As+ samples was found to increase from 1.35 eV (Ta equals 300 degrees Celsius) to 1.41 eV (Ta equals 800 degrees Celsius). The slightly perturbed absorption spectra at near bandgap region interpret that there are still a large amount of near-bandedge defects continuously distributed in the RTA-annealed GaAs:As+ samples. The diminishing of shallow-level defects with at higher annealing temperatures was also observed via the derivative absorption spectra.

[1]  Ci-Ling Pan,et al.  Material and ultrafast optoelectronic properties of furnace-annealed arsenic-ion-implanted GaAs , 1998 .

[2]  H. Dietrich,et al.  Electrical characterization of low temperature GaAs layers, and observation of the extremely large carrier concentrations in undoped material , 1992 .

[3]  S. Benjamin,et al.  Large ultrafast optical nonlinearities in As-rich GaAs , 1994 .

[4]  Eicke R. Weber,et al.  Stoichiometry‐related defects in GaAs grown by molecular‐beam epitaxy at low temperatures , 1989 .

[5]  D. C. Walters,et al.  Native donors and acceptors in molecular‐beam epitaxial GaAs grown at 200 °C , 1992 .

[6]  Michael R. Melloch,et al.  The role of point defects and arsenic precipitates in carrier trapping and recombination in low‐temperature grown GaAs , 1996 .

[7]  M. Hollis,et al.  Picosecond GaAs-Based Photoconductive Optoelectronic Detectors , 1989, OSA Proceedings on Picosecond Electronics and Optoelectronics.

[8]  Semi-insulating GaAs made by As implantation and thermal annealing , 1993 .

[9]  U. Mishra,et al.  Proceedings of low temperature (LT) GaAs and related materials , 1992 .

[10]  Evans,et al.  Anomalous Hall-effect results in low-temperature molecular-beam-epitaxial GaAs: Hopping in a dense EL2-like band. , 1990, Physical review. B, Condensed matter.

[11]  F. Namavar,et al.  Formation of As precipitates in GaAs by ion implantation and thermal annealing , 1993 .

[12]  A. Krotkus,et al.  Picosecond carrier lifetime in GaAs implanted with high doses of As ions: An alternative material to low‐temperature GaAs for optoelectronic applications , 1995 .

[13]  Ci-Ling Pan,et al.  Subpicosecond carrier lifetimes in arsenic-ion-implanted GaAs , 1995 .