Growth Strategy and Physical Properties of the High Mobility P-Type CuI Crystal

Abstract

Acquiring stable binary wide band-gap semiconductor (WBS) materials with high p-type mobility is essential for the development of WBS optoelectronic devices. CuI is a p-type WBS material with a large band gap (3.1 eV) and high exciton binding energy (62 meV). However, the semiconductor characteristics of the CuI single crystal are unknown due to the lack of a large sized and high quality crystal. Our approach focuses on the design of the mineralizer for the hydrothermal method to effectively control the growth habit and the impurity concentration in the crystal. A large size (15 mm  10 mm  1 mm) and high quality CuI single crystal is obtained by using a new mineralizer (NH 4 I þ KI). The crystal shows high p-type mobility (43.9 cm 2 3 V -1 3 S 1-). The strong and sharp band-edge emission at 410 nm indicates that the interband excitonic transition dominates the optical response in the spectrum. Such a binary crystalline material may open the way to new applications in optoelectronic devices.

Room-temperature synthesized copper iodide thin film as degenerate p-type transparent conductor with a boosted figure of merit

“…The wide direct bandgap of CuI (3.1 eV at room temperature) allows for a high transparency in the visible spectral range. Moreover, its exciton binding energy (62 meV) is similar to that of ZnO (22). CuI is a native p-type conductor due to copper vacancies with a high hole mobility (>40 cm 2 V −1· s −1 in bulk) owing to the fairly small effective mass of 0.30m 0 for the light holes (22,23).…”

“…Moreover, its exciton binding energy (62 meV) is similar to that of ZnO (22). CuI is a native p-type conductor due to copper vacancies with a high hole mobility (>40 cm 2 V −1· s −1 in bulk) owing to the fairly small effective mass of 0.30m 0 for the light holes (22,23). It is also possible to improve the hole conductivity further by appropriate iodine doping (24).…”

Structure-property relationships in cubic cuprous iodide: A novel view on stability, chemical bonding, and electronic properties

“…[17][18][19][20]). CuI belongs to a cuprous halide family CuX; it is characterized by the monovalent copper(I) state which is stabilized by tetrahedral coordination to the surrounded four halogen atoms.…”

Luminescence characteristics of CuI film by iodine annealing

“…In recently years, c phase p-type CuI semiconductor has received more and more attention due to its wide band gap (3.1 eV) and large exciton binding energy (62 meV) [1]. These properties make it be a candidate material for applications in the blue light emitting diodes (LEDs) and laser diodes (LDs) [2].…”