Structure investigation of low-temperature-grown GaAsSb, a material for photoconductive terahertz antennas

Abstract

The formation of precipitates after an annealing process in low-temperature-grown GaAs0.6Sb0.4 is observed. We use high-resolution transmission electron microscopy for a detailed structure investigation and demonstrate the functionality of the material, which has a band gap of 0.86 eV, for ultrafast optical switches. The average diameter of the clusters is 5.7 nm in the bulk region, while larger clusters are observed near the interface to a 1.3% lattice mismatched Al0.77In0.23As buffer layer. After an annealing treatment, the sheet resistance is increased by five orders of magnitude to 1.7×108Ω/sq, which is sufficiently high to enable Auston switch operation. We report terahertz (THz) emission from the material measured in a THz time-domain spectroscopy setup. THz generation is demonstrated by using a six interdigital finger metal-semiconductor-metal structure at the feed-point of a log-periodic antenna.

Semiconductors for terahertz photonics applications

“…GaAs 0.6 Sb 0.4 grown on GaAs substrates at temperature of 170 o C had high resistivity after annealing and was used for manufacturing photoconductive THz emitters in [115]. Though the bandgap of this material was only 0.86 eV, these emitters, when activated by Ti:sapphire laser pulses, have shown much worse performance as LTG GaAs devices.…”

Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

“…Therefore, the growth of an antimony-containing compound semiconductor, such as GaAsSb or GaSb, from some suitable material candidates was performed by the MLE method because this type of semiconductor has almost the same lattice constant as a GaAs substrate. GaAsSb and GaSb growth are also used for manufacturing photoconductive THz emitters [118][119][120], THz laser [121] and double HBT structure [122]. GaAsSb/GaAs quantum wells have attracted attention for their potential applications in electronic and optoelectronic devices, and these structures have been fabricated and evaluated in several reports [123][124][125][126][127][128][129][130][131].…”

All-Fiber Centralized Architecture for Parallel Terahertz Sensors

“…Thus, expensive and bulky Ti:Sapphire lasers can be replaced by low cost 1550 nm telecom sources. These materials include LT-InGaAs [8], LT-GaAsSb [9], ionimplanted InGaAs [10] and super-lattice structures with LTInGaAs/InAlAs [11][12].…”