protected void func(BytesColumnVector outV, byte[][] vector, int[] start, int[] length, int i) {
    StringExpr.padRight(outV, i, vector[i], start[i], length[i], maxLength);
  }
Do pad out the CHAR type into the BINARY result, taking into account Unicode...
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/CastCharToBinary.java