Mobility of modulation doped AlGaAs/low-temperature MBE-grown GaAs heterostructures
| Autor: | D. Schulte, S. Subramanian, L. Ungier, J. R. Arthur, K. Bhattacharyya |
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| Rok vydání: | 1995 |
| Předmět: |
Condensed matter physics
Scattering Doping Heterojunction Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter Physics Electronic Optical and Magnetic Materials Condensed Matter::Materials Science chemistry.chemical_compound chemistry Ternary compound Electrical resistivity and conductivity Materials Chemistry Field-effect transistor Electrical and Electronic Engineering Molecular beam Molecular beam epitaxy |
| Zdroj: | Journal of Electronic Materials. 24:359-363 |
| ISSN: | 1543-186X 0361-5235 |
| DOI: | 10.1007/bf02659699 |
| Popis: | A study of the mobility of a novel modulation doped heterostructure in which the channel region is made of low-temperature molecular beam epitaxially grown GaAs (LT-GaAs) and all other layers are grown at normal temperatures is presented for the first time. The resistivity of the as-grown samples(in- situ annealed) is very high, as is that of single layers of bulk LT-GaAs. However, in the presence of light, the resistivity of the LT-GaAs modulation-doped field effect transistor (MODFET) is significantly lower, facilitating reliable Hall measurements. We speculate that the observed decrease in resistivity of the LT-GaAs MODFET is due to the formation of a two-dimensional electron gas (2DEG) at the heterointerface under illumination. A number of samples grown under different growth conditions were investigated. Mobilities for these samples were found to be in the range of 250 to 750 cm2Vs at 300K and ∼3000 to 5500 cm2Vs at 77K. A first-order computer simulation was implemented to calculate the mobility of the 2DEG using the relaxation-time approximation to solve the Boltzmann equation, taking into account different scattering mechanisms. Scattering by the arsenic clusters and by ionized impurities in the LT-GaAs MODFET channel are found to be the two dominant mechanisms limiting the mobility of the LT-GaAs MODFET samples. Experimental values are in good agreement with theoretical results. |
| Databáze: | OpenAIRE |
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