We offer LT-GaAs wafer for THz, detector, ultra-fast-optical experiments and other applications.
1. 2″ LT-GaAs Wafer Specification:
|Diamater(mm)||Ф 50.8mm ± 1mm|
|Thickness||1-2um or 2-3um|
|Marco Defect Density||≤ 5 cm-2|
|Useable Surface Area||≥80%|
|Polishing||Single side polished|
Remark: Other conditions:
1) GaAs substrate should be undoped/semi-insulating with (100)orientation.
2) Growth temperature: ~ 200-250 C
2. LT-GaAs Introduction:
Low-temperature grown GaAs is the most widely used material for the fabrication of photoconductive THz emitters or detectors. Its unique properties are good carrier mobility, high dark resistivity, and subpicosecond carrier lifetimes.
GaAs grown by molecular beam epitaxy (MBE) at temperatures lower than 300 °C (LT GaAs) presents a 1%–2% arsenic excess which depends on the growth temperature Tgand on the arsenic pressure during the deposition. As a result a high density of arsenic antisite defects AsGa is produced and forms a donor miniband close to the center of the band gap. The concentration of AsGa increases with decreasing Tg and can reach 1019–1020 cm-3, which leads to a decrease of the resistivity due to hopping conduction. The concentration of ionized donors AsGa+, which are responsible for the fast electron trapping, depends strongly on the concentration of acceptors (gallium vacancies). The LT-MBE grow GaAs samples are then usually thermally annealed: The excess arsenic precipitates into metallic clusters surrounded by depleted regions of As/GaAs barriers which allow one to recover the high resistivity. The role of the precipitates in the fast carrier recombination process is, however, not yet completely clear. Recently, attempts have been made also to dope LT GaAs during the MBE growth with compensating acceptors, namely with Be, in order to increase the number of AsGa+ : the trapping time reduction was observed for heavily doped samples.
3. LT-GaAs Test Report:
Please click the following to see the LT-GaAs report:
4. THz Generation Process in LT-GaAs
5. Performance of Terahertz Photoconductive Antennas:
Please click the following to see this article:
6. Time Domain Spectra of THz
Below is Time Domain Spectra of THz made from our LT-GaAs wafer
7. Time-resolved Spectrum of LT-GaAs Wafer
8. FAQ of LT-GaAs Wafer
Q: Can LT-GaAs substrate be passivated? Does washing the surface with ultrasonics have any effect on that layer of low temperature GaAs?
A: The LT-GaAs substrate can do passivation treatment. It is no problem that wash the surface of LT-GaAs with low-power ultrasonic waves.
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