Improved InGaAs and InGaAs/InAlAs Photoconductive Antennas Based on (111)-Oriented Substrates

Abstract

The terahertz wave generation by spiral photoconductive antennas fabricated on low-temperature In0.5Ga0.5As films and In0.5Ga0.5As/In0.5Al0.5As superlattices is studied by the terahertz time-domain spectroscopy method. The structures were obtained by molecular beam epitaxy on GaAs and InP substrates with surface crystallographic orientations of (100) and (111)A. The pump-probe measurements in the transmission geometry and Hall effect measurements are used to characterize the properties of LT-InGaAs and LT-InGaAs/InAlAs structures. It is found that the terahertz radiation power is almost four times higher for LT-InGaAs samples with the (111)A substrate orientation as compared to (100). Adding of LT-InAlAs layers into the structure with (111)A substrate orientation results in two orders of magnitude increase of the structure resistivity. The possibility of creating LT-InGaAs/InAlAs-based photoconductive antennas with high dark resistance without compensating Be doping is demonstrated.

Spintronic terahertz emitters: Status and prospects from a materials perspective

“…Table comparing the characteristics of commonly used THz emitters in THz-TDS. For each tick the reference, R, indicates the references that demonstrated achievement of the particular source characteristic, as follows: R1: 17 ; R2: 15,16 ; R3: [12][13][14][15][16] ; R4: [22][23][24] ; R5: 5,26,27 ; R6: 5,25,26,28 ; R7: 33 ; R8: 36,37 ; R9: 39 ; R10: 38 ; R11: 38 ; R12: [39][40][41] ; R13: 40,41 ; R14: 42 ; R15: 39,41 ; R16: 41 ; R17: 47 ; R18: 48,49 ; R19: 48,49 ; R20: 58 ; R21: 57,58 ; R22: 57,58 ; R23: 57 .…”

“…[9][10][11] While all terahertz time-domain spectrometers utilize femtosecond pulses of laser light to create a sub-picosecond transient current or electronic polarization in order to generate pulses of broadband terahertz (THz) frequency radiation, there are a plethora of different materials employed for the THz generation process. THz emitters include photoconductive antennas (employing GaAs [12][13][14][15][16][17][18][19][20][21] or InGaAs [22][23][24] ), organic and inorganic nonlinear crystals (ZnTe, [25][26][27][28][29][30][31][32] GaP, [33][34][35] LiNbO 3 , 36,37 DAST, 38,39 DSTMS, [39][40][41][42] OH1, 39,41,43 and BNA 44 ), and recently, air plasma, [45][46][47][48][49] liquids 50 and metamaterials. 51 The reason for the large diversity of THz emitters employed is becau...…”

Terahertz Photoconductive Antenna Based on a Topological Insulator Nanofilm

“…Another dipole photoconductive antenna, fabricated on a low-temperature grown In 0.5 Ga 0.5 As/In 0.5 Al 0.5 As superlattice, was used as a second antenna for reference. The parameters of similar spiral antenna were previously studied and reported in [33]. The multilayer heterostructure InGaAs/InAlAs for semiconductor PCA was grown on an InP (111) substrate (Figure 1b).…”

Si‐Doping of Low‐Temperature‐Grown GaAs Heterostructures on (100) and (111)A GaAs Substrates

“…The concentration of charged active traps As Ga + can be increased in this way which is useful for terahertz applications. Also, previous studies [ 20,21 ] have shown that LTG structures grew on (111)A substrates and photoconductive antennas on the base of these structures can produce a stronger THz response upon photoexcitation.…”