Growth of mm-thick orientation-patterned GaAs for IR and THZ generation

Cathodoluminescence Study of Orientation-Patterned GaAs Crystals for Nonlinear Optics

“…[2][3][4][5] Orientation-patterned templates can be epitaxially fabricated using molecular-beam epitaxy (MBE). [2][3][4] First, a Ge layer is deposited on a vicinal GaAs substrate (tilted 4°towards {111}B); then, a GaAs layer crystallographically inverted with respect to the GaAs substrate is deposited. This GaAs 001 ð Þ=Ge=GaAsð00 " 1Þ structure is lithographically etched, creating a periodic template of 001 ð Þ substrate ð Þand ð00 " 1Þ (epitaxial layer) oriented GaAs seeds.…”

“…Rapid growth rates (up to 200 lm/h) can be attained using low-pressure HVPE; therefore, layers with thickness exceeding 1 mm can be grown in a single run of 10 h to 12 h of continuous growth. 4 The uniformity of the crystals is very important; one should consider that, during such long growth runs, parasitic nucleation of GaAs on the quartz reactor walls can occur. The formation of these parasitic crystals has the practical consequence of depleting the supply of nutrients, slowing the growth rate, and altering the growth conditions, with corresponding changes in the crystal properties, as well as affecting growth faceting, which can disturb the homogeneity of the domain grating.…”

“…The domain widths range from 20 lm to 2 mm, depending on the pump and signal frequencies. [2][3][4] These crystals are inserted into an optical parametric oscillator (OPO), generating laser sources with wavelengths ranging from 2 lm to the THz range. The signal wavelength range is determined by the choice of the pump laser wavelength and the period of the OP-GaAs grating.…”

“…To meet this requirement, it is desirable to achieve very fast growth rates for the periodic 001 ½ 00 " 1 Â Ã -oriented GaAs domain structure. 4 Hydride vapor-phase epitaxy (HVPE) is a technique fulfilling the requirements for growing thick layers suitable for QPM. The bottlenecks to achieving high conversion efficiency are fabrication of high-quality crystals in order to minimize optical losses, and preservation of the grating period all over the crystal to maintain the efficiency of the nonlinear interaction.…”

Heteroepitaxy, an Amazing Contribution of Crystal Growth to the World of Optics and Electronics

“…Different facilities express different preferences but both types, the wafer fusion bonded [60,72,73] and the MBE assisted polarity inversion [74][75][76], OPGaAs templates are currently in use. Due to long extraordinary efforts mm thick OPGaAs with improved domain fidelity is not a surprise today after a homoepitaxial HVPE growth of OPGaAs on OPGaAs templates (Figure 27a).…”