Lucas, FO;Mitra, A;McNally, PJ;Daniels, S;Bradley, AL;Taylor, DM;Proskuryakov, YY;Durose, K;Cameron, DC

2007

June

Journal of Physics D - Applied Physics

Evaluation of the chemical, electronic and optoelectronic properties of gamma-CuCl thin films and their fabrication on Si substrates

Published

13 ()

FIELD-EFFECT TRANSISTORS MOLECULAR-BEAM EPITAXY ELECTRICAL-CONDUCTIVITY VAPOR-DEPOSITION SOLID-ELECTROLYTE CUPROUS HALIDES COPPER HALIDES ZNO GROWTH GAS

40

3461

3467

CuCl is a I-VII semiconductor material with a direct band gap of similar to 3.4 eV. It exhibits a zincblende structure (gamma-phase) at low temperatures, up to similar to 680 K. Unlike GaN, ZnO and related materials, CuCl has a relatively low lattice mismatch with Si (<0.4%) and a large excitonic binding energy (similar to 190 meV). This suggests the possibility of the fabrication of excitonic-based blue/UV optoelectronic devices on Si with relatively low threading dislocation densities. In this study, CuCl has been deposited and examined as a candidate material for the fabrication of these devices. X-ray diffraction (XRD) measurements confirmed that the deposited films were preferentially oriented in the (1 1 1) plane. Room temperature photoluminescence measurements reveal a strong Z(3) free exciton peak ( 3.232 eV). Both steady state dc and ac impedance spectroscopy experiments suggested that the deposited CuCl is a mixed ionic-electronic semiconductor material. An electronic conductivity of the order of 2.3 x 10(-7) S cm(-1) was deduced to be in coexistence with Cu+ ionic conductivity using irreversible electrodes ( Au), while a total conductivity of the order of 6.5 x 10(-7) S cm(-1) was obtained using reversible electrodes ( Cu) at room temperature. Further to this, we have identified some of the challenges in fabricating an optoelectronic device based on a CuCl/Si hybrid platform and propose some possible solutions.

BRISTOL

0022-3727

10.1088/0022-3727/40/11/030