Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

Abstract

Articles you may be interested inElectrical properties and deep traps spectra of N-polar and Ga-polar AlGaN films grown by molecular beam epitaxy in a wide composition range J. Appl. Phys. 105, 113712 (2009); 10.1063/1.3143012In-plane self-arrangement of high-density InAs quantum dots on GaAsSb ∕ GaAs ( 001 ) by molecular beam epitaxy

Hard thin films

“…One of the attempts was to alter the collection method from the conventional forwards to the backwards mode (Shen et al, 2003) (Figure 21.3(b)), resulting in the maxima of THz frequency up to 20 THz. Other approaches were to enhance the efficiency and output power of THz radiation through the innovative structural design of LT-GaAs, for example, by applying multilayered GaAs (Rihani et al, 2010) and GaAs/n-GaSb heterostructure (Sadia et al, 2012). These technological improvements (higher efficiency and broader bandwidth) have enabled the generation of coherent radiation for a wide spectrum of technical applications in scientific analysis (Jepsen et al, 2011), hazards detection (Davies et al, 2008), and skin cancer identification and so on.…”

Interruption-assisted epitaxy of faceted p-InAs on buffered GaSb for terahertz emitters

“…In addition, an SL was used with the intention of smoothing the ensuing film, as seen in previous studies on AlGaAs=GaAs 14) and metamorphic GaAs=n-GaSb. 6) The RHEED patterns in Fig. 1 show that the InAs epilayer appeared following quasi-2D growth and then favored 3D island faceting.…”

“…2) Recent studies have demonstrated that other viable THz sources may be created by judiciously choosing the material structures. These layers of semiconductors, for example, i-GaAs=n-GaAs, 3) InAs=GaAs quantum dots interspersed in GaAs, 4) an undoped-GaAs=n-GaAs layer on Si, 5) and i-GaAs=n-GaSb, 6) emit THz radiation via acceleration of photoexcited carriers by surface and interface fields. Additionally, Refs.…”

“…Although GaAs=GaSb has a larger percentage of lattice mismatch (7.8%) than InAs= GaSb (0.6%), 10) the GaAs epilayer easily adheres to the GaSb substrate when a growth interruption technique is used. 6) The present scheme does not rely on the Sb soak time and group V (Sb and As) beam supply sequence described in earlier works. 11,12) Rather, in the growth interruption technique, the group III (Ga) source is shuttered, whereas the As flux is maintained.…”

“…The shuttering sequence was repeated for only 2 min because surface smoothing usually occurs during this duration. 6) The spotty RHEED pattern changed to weakly defined quasi-(2 × 4) streaks, which can be thought of as the onset of the quasi-two-dimensional (2D) growth mode.…”