| Summary: | 碩士 === 國立中山大學 === 物理研究所 === 84 === We intend to study the magneto-transport properties of two
dimensional electron gas inδ-doped III-V semiconductors and to
explore the electron's oscillations varied with the external
magnetic field ( 0∼12 T ) Shubnikov-de Haas and Quantum Hall
effect. The carrier concentration can be calculated precisely
after Fourier transformation. The experimental result is as
follows： Due to the negative persistent photo-conductivity
effect, the carrier concentration decreased with theδ-doped
Al0.5Ga0.5Sb/InAs quantum well at low temperature under
illumination. Considering the δ-doped AlAs0.56Sb0.44/Ga0.47
In0.53As quantum well, the electron densities of the first and
second subbands are 26.2 and 6.3 cm-2, respectively, of which
increase to 29.2 and 7.2 cm-2 after low temperature's
illumination. As a matter of fact, a positive persistent photo-
conductivity effect may result after illumination. Other sample
with similar structures to the former one has positive
persistent photo-conductivity effect in view of measured
Quantum Hall effect after illumination.
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