Room-temperature InP/InAsP Quantum Discs-in-Nanowire Infrared Photodetectors

Abstract

The possibility to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on a combined study of design, fabrication, and optoelectronic properties of infrared photodetectors comprising four million n-i-n InP nanowires periodically ordered in arrays. The nanowires were grown by metal-organic vapor phase epitaxy on InP substrates, with either a single or 20 InAsP quantum discs embedded in the i-segment. By Zn compensation of the residual n-dopants in the i-segment, the room-temperature dark current is strongly suppressed to a level of pA/NW at 1 V bias. The low dark current is manifested in the spectrally resolved photocurrent measurements, which reveal strong photocurrent contributions from the InAsP quantum discs at room temperature with a threshold wavelength of about 2.0 μm and a bias-tunable responsivity reaching 7 A/W@1.38 μm at 2 V bias. Two different processing schemes were implemented to study the effects of radial self-gating in the nanowires induced by the nanowire/SiO/ITO wrap-gate geometry. Summarized, our results show that properly designed axial InP/InAsP nanowire heterostructures are promising candidates for broadband photodetectors.

Multiple radial phosphorus segregations in GaAsP core-shell nanowires

“…Nanowire QWs are often assembled in the radial and axial directions in tubular and disc forms, respectively [41][42][43][44]. The current results demonstrate a self-formation of composition varied finite regions within the nanowire in the form of P deficient radial bands encompassed between P rich bands.…”

Temperature dependence of optical properties of InAs/InP quantum rod-nanowires grown on Si substrate

“…Furthermore, NWs with built-in homojunctions or heterojunctions, realized by variation of doping and composition along their length, constitute a new class of promising one dimensional semi conductor heterostructures [13,14]. The insertion of low dimensional quantum heterostructures in NWs adds new degrees of design freedom for optimization of electrical and optical performances [15]. Generally, the VLS approach allows for the growth of quantum rods of any desired height without the limits inherent to the growth of InAs quantum dots using the Stranski-Krastanov (SK) growth mode [16].…”

Nanowire photodetectors based on wurtzite semiconductor heterostructures

“…pronounced polytipism in III-As nanowires has so far hindered the observation of ISB transitions in bottom-up GaAs-based heterostructured nanowires (self-assembled or selectively nucleated).In spite of these limitations, broadband ISB photodetectors were fabricated by planarization and contacting of an InP nanowire array containing a InAs0.55P0.45 quantum wells[175][176][177]. The arrays were synthesized by selective area growth by MOVPE and planarization was performed by spin coating with photoresist S1818.…”