Zero-field time-of-flight characterization of minority-carrier transport in heavily carbon-doped GaAs

Abstract

Minority-carrier electron-diffusion coefficients and lifetimes have been measured in heavily doped p-type GaAs using the zero-field time-of-flight (ZFTOF) technique. The materials studied included C-doped GaAs grown by molecular-beam epitaxy (MBE) using graphite as the dopant source, C-doped GaAs grown by metalorganic chemical-vapor deposition (MOCVD) using CCl4 as the dopant source, and Be-doped GaAs grown by MBE. Room-temperature photoluminescence intensity measurements were made on the structures and the results are compared with ZFTOF measurements of lifetime. The graphite-doped material (p∼1019 cm−3) exhibited diffusion lengths of less than 1000 Å. MOCVD-grown C-doped GaAs, which was optimized by adjusting the growth conditions to maximize the room-temperature photoluminescence intensity, had diffusion lengths comparable to those measured in Be-doped GaAs for hole concentrations of 1×1019 and 5×1019 cm−3. Comparison of photoluminescence intensities also suggests that addition of In to very heavily doped MOCVD-grown GaAs (p≳1020 cm−3) to eliminate the lattice mismatch with respect to the substrate does not result in an improvement in lifetime.

Physical processes of current gain in InAs bipolar junction transistors

“…(3) and the value of T determined above, the minority carrier di usion length in the base, L B , is estimated to be 0:44 m. At the doping concentration in the base, the InAs electron mobility is greater than that of GaAs by a factor of 2-3, thus the corresponding electron di usion lengths would be slightly larger in InAs than in GaAs. As expected, this value of L B is comparable to the values reported in similarly doped p-GaAs [6].…”

Effect of high-temperature annealing on GaInP/GaAs HBT structures grown by LP-MOVPE

“…The measured electron lifetimes of the as-grown intrinsically doped layers are comparable to the best published results. 17 These dependencies agree well with the results of the HBT characterization (Fig. 2).…”

Quantitative description of photoexcited scanning tunneling spectroscopy and its application to the GaAs(110) surface

“…For the light-excited charge carriers we used a minority-carrier lifetime of 5 × 10 −9 s for Zn-doped GaAs following Ref. [53] as well as hole and electron mobility values of 150 and 2400 cm 2 V −1 s −1 , respectively [54]. The irradiance of the incident laser beam was used as the only fitting parameter for the calculation of the illuminated curves.…”