title: Temperature Dependence of Interband Transitions in Wurtzite InP Nanowires.
abstract: Semiconductor nanowires (NWs) formed by non-nitride III-V compounds grow preferentially with wurtzite (WZ) lattice. This is contrary to bulk and two-dimensional layers of the same compounds, where only zincblende (ZB) is observed. The absorption spectrum of WZ materials differs largely from their ZB counterparts and shows three transitions, referred to as A, B, and C in order of increasing energy, involving the minimum of the conduction band and different critical points of the valence band. In this work, we determine the temperature dependence (T = 10-310 K) of the energy of transitions A, B, and C in ensembles of WZ InP NWs by photoluminescence (PL) and PL excitation (PLE) spectroscopy. For the whole temperature and energy ranges investigated, the PL and PLE spectra are quantitatively reproduced by a theoretical model taking into account contribution from both exciton and continuum states. WZ InP is found to behave very similarly to wide band gap III-nitrides and II-VI compounds, where the energy of A, B, and C displays the same temperature dependence. This finding unveils a general feature of the thermal properties of WZ materials that holds regardless of the bond polarity and energy gap of the crystal. Furthermore, no differences are observed in the temperature dependence of the fundamental band gap energy in WZ InP NWs and ZB InP (both NWs and bulk). This result points to a negligible role played by the WZ/ZB differences in determining the deformation potentials and the extent of the electron-phonon interaction that is a direct consequence of the similar nearest neighbor arrangement in the two lattices.
authors: †Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
authors: Attilio
authors: A
authors: Zilli
authors: †Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
authors: Marta
authors: M
authors: De Luca
authors: †Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
authors: Davide
authors: D
authors: Tedeschi
authors: ‡Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia.
authors: H Aruni
authors: HA
authors: Fonseka
authors: †Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
authors: Antonio
authors: A
authors: Miriametro
authors: ‡Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia.
authors: Hark Hoe
authors: HH
authors: Tan
authors: ‡Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200, Australia.
authors: Chennupati
authors: C
authors: Jagadish
authors: †Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
authors: Mario
authors: M
authors: Capizzi
authors: †Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma, Italy.
authors: Antonio
authors: A
authors: Polimeni
keywords: InP nanowires; band-structure critical points; photoluminescence excitation spectroscopy; thermal properties; wurtzite and zincblende structures