Create a Folder in Powershell using a variable

Does anyone know how I can create a folder on a remote server using a variable ?

The script below does create a folder on the remote server but does not add the $NewFTPUser as a folder.

$NewFTPUser = Test
Invoke-Command -ComputerName dc03.domain.com -scriptBlock {
        $Folder = "\\dc03\c$\temp\DC01" + $NewFTPUser
        New-Item -ItemType directory -Force -path $Folder        
        }