Experimental insights toward carrier localization in in-rich InGaAs/InP as candidate for SWIR detection: Microstructural analysis combined with optical investigation
Date
15.01.2023Author
Arbia Marwa BenDemir İlkay
Kaur Navpreet
Saidi Faouzi
Zappa Dario
Comini Elisabetta
Altuntaş İsmail
Maaref Hassen
Metadata
Show full item recordAbstract
Hyperspectral imaging has been flourished thanks to the huge investigation of the infrared spectrum from NIR to
LWIR bands. The ternary InGaAs has been investigated herein in the context of studying the structural dependences
of localization phenomenon by X-ray diffraction (XRD), scanning electron microscopy-energy
dispersive X-ray (SEM-EDX), Raman, ultraviolet–visible (UV–vis), and photoluminescence (PL) techniques.
Using metal-organic vapor phase epitaxy (MOVPE), we succeed to grow the InGaAs directly on InP substrate at
560 ◦C as an active layer with indium concentration exceeding the “golden” value (53%) to enlarge its cutoff
absorption wavelength. X-ray diffraction proved a good crystallinity of the heterostructure with a sharp peak
related to the thick substrate and another peak attributed to the thin layer of InGaAs. Moreover, an interfacial
layer appeared at the logarithmic scale of XRD patterns and was confirmed by Raman analysis. The SEM-EDX
revealed an average indium concentration (62%), almost the growth concentration. However, a cross-section
compositional profile over the heterostructure showed an inhomogeneous distribution of the indium. This is
predictable from the composition fluctuation in the indium-containing alloys and the volatility (surface segregation)
of As (In). On the other side, the optical investigation of InGaAs demonstrated an anomalous behavior of
luminescence versus temperature, manifested by the S-shape feature. This trend stems from the potential fluctuation
induced by the non-uniform distribution of indium. A numerical simulation was developed based on the
localized state ensemble (LSE) model to well-reproduce this anomaly by giving the best fitting parameters and
comparing them with those calculated using the semi-empirical models (Vi˜na and P¨assler). The results reported
here will help in optimizing the epitaxy design of future InGaAs/InP and further studying its surface morphology
and device performance.