How to replace in a multidimensional array, one of its meanings, but as an array?

$rawitems = array(array('nope1' => 'a', 'nope2' => 'b'), array('nope1' => 'c', 'nope2' => 'd'));
$itemskey = array('key1', 'key2');
foreach ($rawitems as $row) {
 $items[] = array_combine($itemskey, $row);
}

So here is the code, but it is necessary that b has become a regular array with a value of b.
Array
(
[0] => array([key1] => a [key2] => array([0]=>b))
[1] => array([key1] => c, [key2] => array([0]=>d))
)
Something like this. I can not understand.