remained in its high conductivity state, with an ON/OFF
ratio of over 7.0 104 at 0.5 V. After a reverse sweep
to 6.0 V (stage 3), the diode remained at the high
conductivity state and did not recover its resistance to
the OFF state (stage 4), indicating the inerasable data
storage characteristic. Moreover, the high conductivity
state still remained in stage 5, suggesting the WORM
memory behavior of the MoS2@ZIF-8 based device,
which is different from the previously reported Ag/Rb-
CD-MOF/Ag memory (resistive random access memory,
RRAM).29 For comparison, the IV behavior of
the pure rGOrGO junction between two rGO electrodes
was also measured (Figure S4 in Supporting
Information), which showed higher current than the
On-state current of the MoS2@ZIF-8 based memory
device after the electrical switching, indicating that a
short circuit did not occur during the operation of the
MoS2@ZIF-8 based device. To explore the stability of
our device, the retention time test was carried out in
the ON and OFF states, respectively (Figure 4b). The ON
and OFF states of the device did not undergo significant
fluctuation even after more than 1.5103 s of test
under ambient conditions at a reading bias of þ0.5 V.
The long retention time indicates the highly stable
information storage capability of our device.