search directory one level deep file

$mu2_file=@()

mu2_file= get-childitem -path C:\temp\text -Recurse -include "mu_*.txt"

the folder C:\temp\text

mu_4342.txt

mu_56546.txt

C:\temp\text\x

mu_5435543.txt

mu_53465464.txt

i only search level 1 deep directory:

mu_4342.txt

mu_56546.txt