We report the solution-phase synthesis and surface processing of 2鈥? 渭
m long single-crystalline IV鈥揤I tin(II) sulfide (SnS) ultrathin nanoribbons, with thicknesses down to 10 n
m, and their use in single nanoribbon based photodetectors. The SnS nanoribbons grow
via a
metastable-to-stable phase transition fro
m zinc blende (ZB) nanospheres to orthorho
mbic nanoribbons; dual-phase inter
mediate heterostructures with zinc blende nanosphere heads and orthorho
mbic nanoribbon tails were observed. Exchange of long, insulating organic oleyla
mine ligands by short, inorganic HS
鈥?/sup> ligands converts the organic SnS nanoribbons into completely inorganic, hydrophilic structures. Field-effect transistor (FET) devices were made from single SnS nanoribbons, both before and after ligand exchange, which exhibit p-type semiconductor behavior. The SnS single nanoribbon based photodetector devices showed highly sensitive and rapid photocurrent responses to illumination by blue, green, and red light. The switching behavior of photocurrent generation and annihilation is complete within approximately 1 ms and exhibits high photoconductivity gains (up to 2.3 脳 104) and good stability. The ON/OFF ratio of the photodetector can be engineered to 80 (4 nA/50 pA) using a small drain current (10 mV) for the all inorganic SnS nanoribbons. This work paves the way for the colloidal growth of low-cost, environmentally benign, single-crystalline narrow band gap semiconductor nanostructures from abundant elements for applications in photodetectors and other nanoscale devices.
Keywords:
colloidal nanoribbons; phase transition; ligand exchange; field-effect transistors; photodetector; tin sulfide