Structural and Optical Properties of Self-Catalyzed Axially Heterostructured GaPN/GaP Nanowires Embedded into a Flexible Silicone Membrane.

Olga Yu Koval,Ivan S Mukhin,George E Cirlin,Igor V Shtrom,Alexey Yu Serov,Maria Tchernycheva,Liliia N Dvoretckaia,Vladimir V Fedorov,Fedor M Kochetkov,Sergey V Fedina,Georgiy A Sapunov,Alexey D Bolshakov,Vladimir Neplokh,Demid A Kirilenko,Regina M Islamova

doi:10.3390/nano10112110

Abstract

Controlled growth of heterostructured nanowires and mechanisms of their formation have been actively studied during the last decades due to perspectives of their implementation. Here, we report on the self-catalyzed growth of axially heterostructured GaPN/GaP nanowires on Si(111) by plasma-assisted molecular beam epitaxy. Nanowire composition and structural properties were examined by means of Raman microspectroscopy and transmission electron microscopy. To study the optical properties of the synthesized nanoheterostructures, the nanowire array was embedded into the silicone rubber membrane and further released from the growth substrate. The reported approach allows us to study the nanowire optical properties avoiding the response from the parasitically grown island layer. Photoluminescence and Raman studies reveal different nitrogen content in nanowires and parasitic island layer. The effect is discussed in terms of the difference in vapor solid and vapor liquid solid growth mechanisms. Photoluminescence studies at low temperature (5K) demonstrate the transition to the quasi-direct gap in the nanowires typical for diluted nitrides with low N-content. The bright room temperature photoluminescent response demonstrates the potential application of nanowire/polymer matrix in flexible optoelectronic devices.

Highlights

Heterostructured III-V nanowires (NWs) are of great interest for both practical application and fundamental research point of view providing new information about the crystal formation at the nanoscale
To study the effect of the active nitrogen flux on the NW growth mechanism, we synthesized the series of samples: (i) GaP NWs stem grown for 1 h; (ii) heterostructured NWs consisting of two segments with an equal growth time (1 h) with a GaPN segment grown on a GaP stem; and (iii) a reference GaP NW sample grown similar to the sample (ii) but without the introduction of activated nitrogen molecular flux
The growth technique allowing the formation of axially heterostructured GaPN/GaP NW on Si (111) via plasma-assisted molecular beam epitaxy (PA-MBE) with N-content up to 1% is reported

Summary

Introduction

Heterostructured III-V nanowires (NWs) are of great interest for both practical application and fundamental research point of view providing new information about the crystal formation at the nanoscale. Geometry and high refractive index of III–V semiconductor NWs can lead to appearance of waveguide and cavity effects allowing more effective light scattering and collection compared to the thin films [4,5,6]. III–V semiconductor NWs were considered as a promising material for light-emitting and light-detecting applications [7,8,9,10]. One of the recent [15,16] approaches to fabricate a flexible optoelectronic device based on free-standing NWs is to embed a NW array into a transparent polymer matrix and remove composite NW/polymer membrane from the wafer [17,18,19]. Materials based on III–V NWs encapsulated into flexible polymer membranes are of great interest in a wide range of applications. Several important implementations including: solar cells [9,10,20,21], infrared laser radiation visualizer [22], light-emitting devices (LEDs) [7,8,23,24,25], terahertz modulators [26,27], thermoelectric device [15], and other flexible devices [28] were reported recently

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Results

Conclusion