Solution 1: Gnome extensions
Install the extension Start Overlay in Application View to use the Super key alone to open the Application overview.
In addition, install the extension ESC to close overview from applications list to have Esc return you to your desktop rather than to the overview.
In Ubuntu 20.04, use a forked extension: ESC to close overview from applications list | UPDATED by paperthin or ESCape Overview.
Solution 2: ksuperkey (more universal approach that allows you to do whatever you want with super)
With a utility
ksuperkey, you can remap a press/release of the super key alone to any key combination.
ksuperkey is not available in the standard Ubuntu repositories. Thus, you need to compile it yourself according to the instructions on the ksuperkey Github site.
In this case, you would lauch
ksuperkey with the command `ksuperkey -e 'Super_L=Super_L:a'. This will remap hitting super alone to the key combination needed to launch the applications menu.
- The binding of super to show the overview in Gnome Shell needs to be disabled first. Use the command
gsettings set org.gnome.mutter overlay-key '', or alternatively, use dconf-editor to change the value of that key.
- You can autostart
ksuperkey using a .desktop file that you place in your ~/.config/autostart folder.
The contents of this
ksuperkey.desktop file may look as:
Comment=Map super key
Exec=sh -c "sleep 0.4 ; ksuperkey -e 'Super_L=Super_L:a'"
Optionally, install the extension ESC to close overview from applications list ( ESC to close overview from applications list | UPDATED on Ubuntu 20.04) to have Esc return you to your desktop rather than to the overview.