The D sharp half-diminished chord is a 4-note chord consisting of the notes D#, F#, A and C#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as D#m7b5.
Chords that are a subset of D#m7b5. These contain less notes but all of them are included in D#m7b5.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the D#m7b5 chord. Feel free to save or share the image as needed.