Conductivity analysis of n-GaAs molecular beam epitaxial layers using multicarrier fitting

Abstract

We have set up a model for the energy-dependent lifetime, including the effects of the charge carrier collisions with ionized impurities, polar optical phonons, and space charge. The model is then used to compute the mobility spectrum at each temperature, which used to compute the pertinent magnetic-field-dependent Hall parameters. The computed Hall parameters compared can then be measured values to estimate the validity of the lifetime model and parameters. The method has been applied to two n-GaAs∕SI–GaAs epitaxial layers containing two types of carriers. The magnetic field dependence of the Hall voltage has been observed in the studied GaAs layers. We present the numerical solution of the neutrality equation, which contains all sources of charges present in the sample, and numerical integration of the total relaxation times ⟨τ⟩ so combined that is possible to obtain the mobility of the partial charges and their part in the whole conductivity of the layer.

A Model of Numerical Calculation of Conductivity for III-V MBE Epilayers Using a Hall Device

“…The InAs samples have the lowest (Table 2). The results are presented in Figures 3, 4, 5, 6, 7, 8, 9, and 10 with the parameters used to solve the neutrality equation (according to [3,32]). In addition to the results presented in [28], we provide the Hall curves calculated by using the dependence = ⟨ 2 ,ℎ ⟩/⟨ ,ℎ ⟩ 2 and the calculated values of , , and 2 versus temperature in Figures 11, 12, 13, and 14. we used the metallurgical thickness of the epitaxial layer, which allowed us to calculate the conformity between the thickness values used to solve for the concentration and resistivity versus temperature.…”

“…In 0.53 Ga 0.47 As layers were deposited by MBE on SI-InP and GaAs as well as SI-GaAs. We carried out the calculations as described previously [3] for a few samples of InAs, In 0.53 Ga 0.47 As and GaAs with different charge carrier concentrations [3,[26][27][28][29][30][31][32]. The procedure consisted of the following steps:…”

“…Structural inaccuracy, especially in layered structures, is one factor that affects how the magnitude of a magnetic field influences measured charge transport properties [3]. While studying the transport properties of HgCdTe layers, Gold and Nelson [4] reported on the influence of different charge carriers using Hall characterisation.…”

“…These sources form the parts used to solve the neutrality equation, and the solution is obtained by numerical computer calculation. The values of 2.14 ⋅ 10 such charge carrier sources are chosen such that the calculated concentration curve approximates the experimental data [3,[26][27][28][29][30][31][32], as demonstrated for our samples (Table 2) by the example in Figure 3. We believe that the measured conductivity is affected by the presence of different donors in the semiconductor layers.…”

“…These investigators suggested that their improved (QMSA) method has sufficient reliability, versatility, and sensitivity for their proposed analysis which is fully computer-automated, using magnetic field dependence data as input. Our approach accounts for several sources of charge carriers as components contribution to the total conductivity of a semiconductor layer [3]. These sources form the parts used to solve the neutrality equation, and the solution is obtained by numerical computer calculation.…”