How to list file with time stamp?

I would like to list files in a directory with correct time and date the files were created. But the following code gave me time stamp of December 31 1969 19:00:00 when the files are recently created. How do I get the right time and date?

$dir = opendir("temp_dir");
while (($file = readdir($dir)) !== false)
{

$ftime = date("F d Y H:i:s.",filemtime($file));
echo $file.' '. $ftime;

}

Thanks in advance.

 

I figured it out myself. Sorry. I need to include the file path to make it work.