Photoluminescence model of sulfur passivated p-InP nanowires

Abstract

The effect of ammonium polysulfide solution, (NH₄)₂S(x), on the surface passivation of p-doped InP nanowires (NWs) was investigated by micro-photoluminescence. An improvement in photoluminescence (PL) intensity from individual NWs upon passivation was used to optimize the passivation procedure using different solvents, sulfur concentrations and durations of passivation. The optimized passivation procedure gave an average of 24 times improvement in peak PL intensity. A numerical model is presented to explain the PL improvement upon passivation in terms of a reduction in surface trap density by two orders of magnitude from 10¹² to 10¹⁰ cm⁻², corresponding to a change in surface recombination velocity from 10⁶ to 10⁴ cm s⁻¹. The diameter dependence of the PL intensity is investigated and explained by the model. The PL intensity from passivated nanowires decreased to its initial (pre-passivation) value over a period of seven days in ambient air, indicating that the S passivation was unstable.

(Invited) Novel Luminescent Materials Based on Semiconductor Nanowires

“…In contrast, AlInAs/InP heterostructures are expected to be type II, resulting in spatial separation of electrons and holes. The peak near 843 nm in Figure 4 is consistent with the expected wurtzite bandgap of the InP barrier layers [4]. The samples all show a broad peak at higher wavelength, which is attributed to the InAsP QDs.…”

Пассивация поверхности GaAs нитевидных нанокристаллов с помощью молекулярного наслаивания AlN

“…Аналогично случаю объемных матери-алов, их наличие может приводить к пинингу уровня Ферми [1,2], что может отрицательно сказываться на работе приборов на основе ННК вследствие их неболь-ших диаметров, соотносящихся с шириной создаваемых приповерхностных обедненных слоев. Для решения этой проблемы, как и в случае объемных полупроводников, особое внимание уделяется различным способам пасси-вации поверхности [3][4][5][6].…”

Nonradiative Recombination Mechanism in Phosphor-Free GaN-Based Nanowire White Light Emitting Diodes and the effect of Ammonium Sulfide Surface Passivation

“…However, the device performance can be remarkably improved by using surface passivation with dielectric materials. Several materials have been reported for the surface passivation of III-V semiconductors including SiO 2 , SiN x and sulfide [13][14][15]. Hashizume et al demonstrated that SiN x passivation can reduce GaN surface band bending [16] and decrease the charged surface state density.…”

“…Hashizume et al demonstrated that SiN x passivation can reduce GaN surface band bending [16] and decrease the charged surface state density. The sulfur surface passivation technique was reported for the effective removal of surface states and recovering the band-edge emission of InAs nanowires [15]. It can also lead to the reduction in surface trap density and surface recombination velocity of InP nanowires, resulting in the enhanced photoluminescence emission [15,17].…”

“…The sulfur surface passivation technique was reported for the effective removal of surface states and recovering the band-edge emission of InAs nanowires [15]. It can also lead to the reduction in surface trap density and surface recombination velocity of InP nanowires, resulting in the enhanced photoluminescence emission [15,17]. In addition, sulfurpassivation can lead to the removal of the native oxide layer on InP wire surface, and the In-S bond formation may result in the reduced densities of mid-gap surface states [18].…”